Liquid ejection device and printhead

Abstract

The present application provides a liquid ejection device and a print head that can solve problems caused by the temperature detection section provided inside the print head. The liquid ejection device includes a control circuit that outputs a control signal, a drive signal output circuit that outputs a drive signal, and a print head that receives the control signal and the drive signal and ejects a liquid, the print head including a piezoelectric element that receives the drive signal and is driven, a vibrating plate that deforms under the driving of the piezoelectric element, a pressure chamber substrate that is provided with a plurality of pressure chambers whose volumes change according to the deformation of the vibrating plate, a switching circuit that switches whether to supply the drive signal to the piezoelectric element, a wiring substrate that is provided with the switching circuit, and a temperature detection section that detects temperature information of the pressure chambers, and the temperature detection section inputs the temperature information detected during a period in which the switching circuit does not supply the drive signal to the piezoelectric element to the control circuit.

Description

Technical Field

[0001] This invention relates to a liquid ejection device and a printhead. Background Technology

[0002] In liquid ejection devices that eject liquid, a configuration with a printhead is known, which includes a piezoelectric element, a pressure chamber, and a nozzle communicating with the pressure chamber. Furthermore, the printhead changes the volume of the pressure chamber by driving the piezoelectric element, thereby ejecting liquid supplied to the pressure chamber from the nozzle. In such liquid ejection devices, a configuration is known where ejection control suitable for the ink temperature is achieved by driving and controlling the piezoelectric element according to the temperature of the ink stored in the printhead. For example, Patent Document 1 discloses a liquid ejection device and a liquid ejection head (printhead) that, by having a temperature detection unit inside the printhead, which includes a piezoelectric element, a pressure chamber, and a nozzle, detects the temperature of the pressure chamber storing the ink, thereby reducing the temperature difference between the detected temperature and the temperature inside the pressure chamber and improving the accuracy of the pressure chamber temperature detection.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-124599

[0004] However, in the liquid ejection device described in Patent Document 1, since the printhead has a temperature detection unit inside, there is room for further improvement in the possibility of a decrease in the accuracy of the temperature detection of the pressure chamber. Summary of the Invention

[0005] One embodiment of the liquid ejection device according to the present invention comprises: a control circuit for outputting a control signal; a drive signal output circuit for outputting a drive signal; and a printhead for receiving the control signal and the drive signal and ejecting liquid. The printhead includes: a piezoelectric element comprising a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located between the first electrode and the second electrode in a stacking direction of the first electrode, the second electrode, and the piezoelectric body, and the piezoelectric element is driven by the drive signal; and a vibrating plate located on one side of the piezoelectric element in the stacking direction, and driven by the piezoelectric element. The device includes: a deformation chamber substrate located on one side of the stacking direction relative to the vibrating plate, and having multiple pressure chambers whose volume varies according to the deformation of the vibrating plate; a switching circuit for switching whether to supply the drive signal to the piezoelectric element; a wiring substrate having the switching circuit; and a temperature detection unit located on the other side of the stacking direction relative to the vibrating plate and electrically connected to the wiring substrate, which detects the temperature information of the pressure chambers. The liquid ejection device inputs the temperature information detected by the temperature detection unit to the control circuit during the period when the switching circuit does not supply the drive signal to the piezoelectric element.

[0006] One embodiment of the printhead of the present invention is to receive a control signal output by a control circuit and a drive signal output by a drive signal output circuit and eject liquid. The printhead comprises: a piezoelectric element including a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located between the first electrode and the second electrode in a stacking direction in which the first electrode, the second electrode, and the piezoelectric body are stacked, and the piezoelectric element is driven by the drive signal; a vibrating plate located on one side of the stacking direction relative to the piezoelectric element and deformed under the drive of the piezoelectric element; a pressure chamber substrate located on the same side of the stacking direction relative to the vibrating plate and provided with a plurality of pressure chambers whose volume varies according to the deformation of the vibrating plate; a switching circuit for switching whether to supply the drive signal to the piezoelectric element; a wiring substrate provided with the switching circuit; and a temperature detection unit located on the other side of the stacking direction relative to the vibrating plate and electrically connected to the wiring substrate, and detecting temperature information of the pressure chambers. The printhead outputs the temperature information detected by the temperature detection unit during the period when the switching circuit does not supply the drive signal to the piezoelectric element. Attached Figure Description

[0007] Figure 1 This is a diagram showing the general structure of a liquid ejection device.

[0008] Figure 2 This is a diagram illustrating the functional structure of a liquid ejection device.

[0009] Figure 3 This is a diagram showing the configuration of the drive circuit.

[0010] Figure 4 This is a diagram showing the configuration of the drive signal selection circuit.

[0011] Figure 5 This is a diagram used to illustrate the relationship between the latch signal LAT, the conversion signal CH, the clock signal SCK, the head control signal DI, and the selection signal S.

[0012] Figure 6 This is a diagram illustrating an example of the data structure of the head control signal DI.

[0013] Figure 7 It is a diagram representing the decoded content of the decoder.

[0014] Figure 8 This is a diagram showing the configuration of the selection circuit corresponding to the piezoelectric element.

[0015] Figure 9 This is a diagram showing an example of the signal waveform of the drive signal COM.

[0016] Figure 10 This is a diagram illustrating an example of the head control signal DI.

[0017] Figure 11 This is a diagram representing a specific example of the decoder's decoded content.

[0018] Figure 12 It means that it was supplied Figure 11 The diagram shows the drive signal VOUT output from the selection circuit when the selection signal S is shown.

[0019] Figure 13 This is an exploded 3D view showing the structure of the ejection module.

[0020] Figure 14 This is a top view of the ejection module 22.

[0021] Figure 15 It means Figure 14 The cross-sectional view of section IV-IV shown.

[0022] Figure 16 yes Figure 15 Detailed diagram of the main parts.

[0023] Figure 17 It means Figure 14 The sectional view of section VI-VI shown.

[0024] Figure 18 This is a diagram illustrating an example of the timing for acquiring the temperature of the ejection module.

[0025] Figure 19 This is a diagram illustrating an example of the timing for acquiring the temperature of the ejection module in a modified example.

[0026] Explanation of reference numerals in the attached figures

[0027] 1…Liquid ejection device, 2…Ink container, 10…Control mechanism, 20…Print head, 21…Carriage, 22…Ejection module, 24…Temperature detection circuit, 26…Temperature information output circuit, 30…Moving mechanism, 31…Carriage motor, 32…Circular belt, 40…Conveying mechanism, 41…Conveying motor, 42…Conveying roller, 50…Drive circuit, 52…Reference voltage signal output circuit, 60…Piezoelectric element, 90…Linear encoder, 100…Control circuit, 200…Drive signal selection circuit, 210…Selection control circuit, 222a…First register, 222b…Second register, 224a…First latch circuit, 224b…Second latch circuit 226…Decoder, 230…Selection circuit, 232…Inverter, 234…Transmission gate, 260…Control logic circuit, 261…SP register group, 262…Selection control signal generation unit, 270…Selection signal output unit, 310…Pressure chamber substrate, 311…Partition wall, 312…Pressure chamber, 312a, 312b…End, 315…Connecting plate, 316…Nozzle connecting channel, 317…First manifold section, 318…Second manifold section, 319…Supply connecting channel, 320…Nozzle plate, 321…Nozzle, 330…Protective substrate, 331…Holding part, 332…Through hole, 340…Housing component, 341…Storage 342…Third manifold section, 343…Connection port, 344…Supply port, 345…Moldable substrate, 346…Sealing film, 347…Fixed substrate, 348…Opening, 349…Moldable section, 350…Vibrating plate, 351…Elastic film, 352…Insulating film, 360…First electrode, 360a, 360b…End, 370…Piezoelectric element, 370a, 370b…End, 371…Groove, 380…Second electrode, 380a, 380b…End, 385…Wiring section, 391…Independent lead electrode, 392…Common lead electrode, 392a, 392b…Extension section, 393, 393a, 393b…Measurement section Fixed lead electrode, 400… manifold, 401… resistor wiring, 410… active part, 415… inactive part, 420… wiring substrate, 421, 500… integrated circuit, 510… modulation circuit, 512… adder, 513… adder, 514… comparator, 515… inverter, 516… integral attenuator, 517… attenuator, 520… gate drive circuit, 521, 522… gate driver, 550… amplifier circuit, 560… demodulation circuit, 570, 572… feedback circuit, C1~C5, C7… capacitor, D1… diode, L1… inductor, M1, M2… transistor, P… dielectric, R1~R6… resistor. Detailed Implementation

[0028] Hereinafter, preferred embodiments of the present invention will be described using the accompanying drawings. The drawings are for ease of explanation. Furthermore, the embodiments described below do not unduly limit the scope of the invention as described in the claims. Additionally, not all of the configurations described below are essential components of the present invention.

[0029] 1. Structure of the liquid ejection device

[0030] Figure 1 This diagram shows a schematic configuration of the liquid ejection device 1. In this embodiment, the liquid ejection device 1 is described using a serial printing inkjet printer as an example. This serial printing inkjet printer forms an image on the medium P by reciprocating a carriage 21 carrying a printhead 20 that ejects ink (as an example of liquid) along the scanning axis and ejecting ink onto the medium P being transported in the transport direction. The medium P used in this liquid ejection device 1 can be any printing material such as printing paper, resin film, or fabric.

[0031] like Figure 1 As shown, the liquid ejection device 1 includes an ink container 2, a control mechanism 10, a carriage 21, a moving mechanism 30, and a conveying mechanism 40.

[0032] The ink container 2 stores various types of ink that can be sprayed onto the medium P. Examples of ink colors stored in the ink container 2 include black, cyan, magenta, yellow, red, and gray. The ink container 2 used to store such ink can be an ink cartridge, a pouch-shaped ink sac made of a flexible film, or an ink canister that can be refilled.

[0033] The control mechanism 10 includes processing circuits such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array) and storage circuits such as semiconductor memory, and controls the various elements of the liquid ejection device 1 including the printhead 20.

[0034] The carriage 21 carries the printhead 20 and is fixed to the annular belt 32 included in the moving mechanism 30. In addition, the ink container 2 can also be mounted on the carriage 21.

[0035] The control signal Ctrl-H for controlling the printhead 20 and the drive signal COM for driving the printhead 20 are output from the control mechanism 10 and are mounted on the carriage 21. Additionally, ink stored in the ink container 2 is supplied to the printhead 20 via a tube (not shown). Furthermore, the printhead 20 ejects the ink supplied from the ink container 2 according to the input control signal Ctrl-H and drive signal COM.

[0036] The moving mechanism 30 includes a carriage motor 31 and an annular belt 32. The carriage motor 31 operates according to the control signal Ctrl-C input from the control mechanism 10. The annular belt 32 rotates as the carriage motor 31 operates. As a result, the carriage 21, fixed to the annular belt 32, reciprocates on the scanning axis. That is, the carriage 21 reciprocates along the scanning axis that intersects the conveying direction of the conveying medium P.

[0037] The conveying mechanism 40 includes a conveying motor 41 and a conveying roller 42. The conveying motor 41 operates according to the control signal Ctrl-T input from the control mechanism 10. The conveying roller 42 rotates as the conveying motor 41 operates. Along with the rotation of the conveying roller 42, the medium P is conveyed in the conveying direction.

[0038] As described above, the liquid ejection device 1, in conjunction with the conveying mechanism 40 for conveying the medium P and the moving mechanism 30 for reciprocating the carriage 21, causes the print head 20 mounted on the carriage 21 to eject ink onto the medium P, thereby causing the ink to fall at any position on the surface of the medium P and forming the desired image on the medium P.

[0039] 2. Functional Composition of Liquid Ejection Device

[0040] Next, the functional configuration of the liquid ejection device 1 will be explained. Figure 2 This is a diagram illustrating the functional configuration of the liquid ejection device 1. (For example...) Figure 2 As shown, the liquid ejection device 1 includes a control mechanism 10, a print head 20, a carriage motor 31, a conveyor motor 41, and a linear encoder 90.

[0041] The control mechanism 10 includes a drive circuit 50, a reference voltage signal output circuit 52, and a control circuit 100. The control circuit 100 includes, for example, a processing circuit such as a CPU or FPGA and a storage circuit such as a semiconductor memory. Image information signals containing image data are input to the control circuit 100 from an external device such as a host computer that is communicatively connected to the liquid ejection device 1. The control circuit 100 generates various signals for controlling the liquid ejection device 1 based on the input image information signals and outputs them to the corresponding components.

[0042] In a specific example, in addition to the image information signal mentioned above, a detection signal based on the scanning position of the carriage 21 is also input from the linear encoder 90 to the control circuit 100. The control circuit 100 determines the scanning position of the print head 20 mounted on the carriage 21 based on the input detection signal. Furthermore, the control circuit 100 generates and outputs various signals corresponding to the scanning position of the print head 20 and the image information signal.

[0043] In detail, the control circuit 100 generates a control signal Ctrl-C for controlling the movement of the print head 20 along the scanning axis based on the scanning position of the print head 20, and outputs it to the carriage motor 31. This causes the carriage motor 31 to operate, thereby controlling the movement and scanning position of the print head 20 mounted on the carriage 21 along the scanning axis. Additionally, the control circuit 100 generates a control signal Ctrl-T for controlling the transport of the medium P, and outputs it to the transport motor 41. This causes the transport motor 41 to operate, thereby controlling the movement of the medium P along the transport direction. Furthermore, the control signal Ctrl-C can also be input to the carriage motor 31 after signal conversion via a drive circuit (not shown), and the control signal Ctrl-T can also be input to the transport motor 41 after signal conversion via a drive circuit (not shown).

[0044] In addition, the control circuit 100 generates head control signals DI1 to DIn, a conversion signal CH, a latch signal LAT, and a clock signal SCK as control signals Ctrl-H for controlling the print head 20 based on the image information signal input from the external device and the scanning position of the print head 20 input from the linear encoder 90, and outputs them to the print head 20.

[0045] Additionally, the control circuit 100 generates a temperature acquisition request signal TD at a predetermined timing to acquire the temperature of the print head 20 and outputs it to the print head 20. Furthermore, the temperature information signal TI output by the print head 20 based on the temperature acquisition request signal TD is input to the control circuit 100. That is, the control circuit 100 receives a temperature information signal TI containing temperature information of the print head 20. The control circuit 100 then corrects the control signals Ctrl-H, Ctrl-C, and Ctrl-T based on the input temperature information signal TI.

[0046] Furthermore, the control circuit 100 outputs a basic drive signal dO as a digital signal to the drive circuit 50. After performing digital-to-analog conversion on the input basic drive signal dO, the drive circuit 50 amplifies the converted analog signal by stage D to generate a drive signal COM, which is then output to the print head 20. That is, the basic drive signal dO output by the control circuit 100 is a digital signal that defines the waveform of the drive signal COM. Here, the basic drive signal dO only needs to define the waveform of the drive signal COM output by the drive circuit 50, but it can also be an analog signal. Further details about the drive circuit 50 will be described later.

[0047] The reference voltage signal output circuit 52 generates a reference voltage signal VBS and outputs it to the print head 20. The reference voltage signal VBS output by the reference voltage signal output circuit 52 is a potential signal that serves as the driving reference for the piezoelectric element 60 (described later). For example, it can be a signal that is constantly at ground potential, or a DC voltage signal that is constantly at a potential of 5.5V or 6V. The reference voltage signal output circuit 52 can also be integrated with the drive circuit 50.

[0048] The printhead 20 has ejection modules 22-1 to 22-n and a temperature information output circuit 26. In addition, the ejection modules 22-1 to 22-n respectively include a drive signal selection circuit 200, a temperature detection circuit 24 and piezoelectric elements 60[1] to 60[m].

[0049] The ejection module 22-1 is fed by the head control signal DI1, the conversion signal CH, the latch signal LAT, the clock signal SCK, the drive signal COM output by the drive circuit 50, and the reference voltage signal VBS output by the reference voltage signal output circuit 52.

[0050] The clock signal SCK, latch signal LAT, conversion signal CH, head control signal DI1, and drive signal COM input to the ejection module 22-1 are input to the drive signal selection circuit 200. The drive signal selection circuit 200 selects or deselects the signal waveform of the drive signal COM according to the input clock signal SCK, latch signal LAT, conversion signal CH, and head control signal DI1, thereby generating drive signals VOUT[1] to VOUT[m]. Furthermore, the drive signal selection circuit 200 independently outputs the generated drive signals VOUT[1] to VOUT[m] to one end of the corresponding piezoelectric element 60[1] to 60[m]. In addition, the other end of the piezoelectric element 60[1] to 60[m] is commonly input to the reference voltage signal VBS. Moreover, the piezoelectric element 60[1] to 60[m] is driven by the potential difference between the independently input drive signals VOUT[1] to VOUT[m] and the commonly input reference voltage signal VBS. The ejection module 22-1 ejects ink in amounts corresponding to the driving of each of the piezoelectric elements 60[1] to 60[m].

[0051] Here, in the printhead 20 of this embodiment, the driving signal VOUT[1] corresponds to the piezoelectric element 60[1], and the driving signal VOUT[m] corresponds to the piezoelectric element 60[m]. That is, the explanation will focus on the end where the driving signal VOUT[1] generated by the driving signal selection circuit 200 is input to the piezoelectric element 60[1], and the end where the driving signal VOUT[m] generated by the driving signal selection circuit 200 is input to the piezoelectric element 60[m].

[0052] Here, piezoelectric elements 60[1] to 60[m] all have the same configuration, and are sometimes referred to as piezoelectric element 60 when there is no need to distinguish them. In this case, the piezoelectric element 60 is described as having a drive signal VOUT supplied to one end as drive signal VOUT[1] to VOUT[m]. That is, the piezoelectric element 60 is sometimes described as being driven based on the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS supplied to the other end.

[0053] In addition, the temperature detection circuit 24 of the ejection module 22-1 detects the temperature of the ejection module 22-1. Moreover, the temperature detection circuit 24 outputs the detected temperature of the ejection module 22-1 as temperature detection information TH1 to the temperature information output circuit 26.

[0054] Here, the ejection modules 22-2 to 22-n differ only in the input and output signals, have the same structure as the ejection module 22-1, and perform the same actions.

[0055] That is, the ejection module 22-n is input with clock signal SCK, latch signal LAT, conversion signal CH, head control signal DIn, drive signal COM, and reference voltage signal VBS. Furthermore, the drive signal selection circuit 200 of the ejection module 22-n selects or deselects the signal waveform of the drive signal COM based on the input clock signal SCK, latch signal LAT, conversion signal CH, and head control signal DIn, thereby generating drive signals VOUT[1] to VOUT[m]. The drive signals VOUT[1] to VOUT[m] generated by the drive signal selection circuit 200 of the ejection module 22-n are input to one end of the corresponding piezoelectric elements 60[1] to 60[m] of the ejection module 22-n. The other end of the piezoelectric elements 60[1] to 60[m] of the ejection module 22-n is input with the reference voltage signal VBS. Therefore, the piezoelectric elements 60[1] to 60[m] of the ejection module 22-n are driven, thereby ejecting an amount of ink from the ejection module 22-n corresponding to the driving of the piezoelectric elements 60[1] to 60[m]. Furthermore, the temperature detection circuit 24 of the ejection module 22-n detects the temperature of the ejection module 22-n and outputs the detected temperature as temperature detection information THn.

[0056] In the following description, without distinguishing between ejection modules 22-1 to 22-n, they are sometimes referred to as ejection module 22. In this case, the description will focus on the ejection module 22 receiving a clock signal SCK, a latch signal LAT, a conversion signal CH, a head control signal DI, a drive signal COM, and a reference voltage signal VBS, and outputting temperature detection information TH indicating the temperature of the ejection module 22.

[0057] The temperature information output circuit 26 receives temperature detection information TH1 to THn output from the temperature detection circuits 24 of each of the ejection modules 22-1 to 22-n, and a temperature acquisition request signal TD output from the control circuit 100. The temperature information output circuit 26 amplifies and holds the temperature detection information TH1 to THn. Furthermore, based on the temperature acquisition request signal TD input from the control circuit 100, the temperature information output circuit 26 outputs the corresponding signal from the amplified signals of the held temperature detection information TH1 to THn as a temperature information signal TI. This temperature information output circuit 26 includes: an amplification circuit for amplifying the temperature detection information TH1 to THn; a processor such as a microcomputer that receives the input temperature acquisition request signal TD and outputs the amplified temperature information signal TI; and a storage circuit for amplifying and holding the temperature detection information TH1 to THn.

[0058] In addition, the temperature information output circuit 26 can also retain the temperature detection information TH1 to THn output by the temperature detection circuit 24 of the ejection modules 22-1 to 22-n respectively, and amplify the retained temperature detection information TH1 to THn according to the temperature acquisition request signal TD input from the control circuit 100, and output the amplified signal as the temperature information signal TI.

[0059] As described above, the liquid ejection device 1 of this embodiment includes: a control circuit 100 that outputs a control signal Ctrl-H including a clock signal SCK, a latch signal LAT, a conversion signal CH, and a head control signal DI; a drive circuit 50 that outputs a drive signal COM; and a printhead 20 that receives the control signal Ctrl-H and the drive signal COM, including the clock signal SCK, the latch signal LAT, the conversion signal CH, and the head control signal DI, and ejects ink. In other words, the printhead 20 receives the clock signal SCK, the latch signal LAT, the conversion signal CH, and the head control signal DI output by the control circuit 100 and the drive signal COM output by the drive circuit 50 and ejects ink.

[0060] 3. Composition of the drive circuit

[0061] Next, the structure and operation of the drive circuit 50 for the output drive signal COM will be explained. Figure 3 This is a diagram showing the configuration of the drive circuit 50. The drive circuit 50 includes an integrated circuit 500, an amplifier circuit 550, a demodulation circuit 560, feedback circuits 570 and 572, and other electronic components.

[0062] Integrated circuit 500 has multiple terminals, including terminals In, Bst, Hdr, Sw, Gvd, Ldr, Gnd, Vfb, and Ifb. Integrated circuit 500 is electrically connected to an external substrate (not shown) via these terminals. Additionally, integrated circuit 500 includes a DAC (Digital to Analog Converter) 511, a modulation circuit 510, and a gate drive circuit 520.

[0063] DAC511 converts the input digital signal's fundamental drive signal dO into an analog signal's fundamental drive signal aO and outputs it to the modulation circuit 510. The amplified signal of the fundamental drive signal aO output by DAC511 is equivalent to the drive signal COM. That is, the fundamental drive signal aO is equivalent to the target signal before amplification of the drive signal COM, and the fundamental drive signals dO and aO define the signal waveform of the drive signal COM.

[0064] The modulation circuit 510 generates a modulated signal Ms after modulating the basic drive signal aO, and outputs it to the gate drive circuit 520. The modulation circuit 510 includes adders 512 and 513, comparator 514, inverter 515, integrator attenuator 516, and attenuator 517.

[0065] The integrator attenuator 516 attenuates and integrates the drive signal COM input via terminal Vfb, and outputs it to the - input terminal of adder 512. The + input terminal of adder 512 is input with the basic drive signal aO. Furthermore, adder 512 outputs the voltage obtained by subtracting the voltage of the - input terminal from the voltage of the + input terminal and integrating it to the + input terminal of adder 513.

[0066] Attenuator 517 attenuates the high-frequency component of the drive signal COM input via terminal Ifb and outputs the voltage to the - input terminal of adder 513. The voltage output from adder 512 is input to the + input terminal of adder 513. Furthermore, adder 513 generates a voltage signal Os by subtracting the voltage from the - input terminal from the voltage at the + input terminal and outputs it to comparator 514.

[0067] Comparator 514 outputs a modulated signal Ms, which is a pulse modulated signal derived from the voltage signal Os input from adder 513. Specifically, comparator 514 generates and outputs a modulated signal Ms that is at a high level (H) when the voltage value of the voltage signal Os input from adder 513 rises above a predetermined threshold Vth1, and at a low level (L) when the voltage value of the voltage signal Os falls below a predetermined threshold Vth2. Here, the thresholds Vth1 and Vth2 are set to a relationship where threshold Vth1 ≥ threshold Vth2.

[0068] The modulated signal Ms output by comparator 514 is input to gate driver 521 in gate driver circuit 520, and also to gate driver 522 in gate driver circuit 520 via inverter 515. That is, signals with exclusive logic levels are input to gate driver 521 and gate driver 522. Here, the exclusive logic level includes the case where the logic levels of the signals input to gate driver 521 and gate driver 522 will not simultaneously reach level H. Therefore, modulation circuit 510 can also replace inverter 515 or include a timing control circuit to control the timing of the modulated signal Ms input to gate driver 521 and the signal after the logic level of the modulated signal Ms input to gate driver 522 is inverted.

[0069] The gate drive circuit 520 includes a gate driver 521 and a gate driver 522. The gate driver 521 generates an amplified control signal Hgd by level shifting the modulation signal Ms output from the comparator 514, and outputs it from the terminal Hdr.

[0070] Specifically, a voltage is supplied to the high-side of the power supply voltage to the gate driver 521 via terminal Bst, and a voltage is supplied to the low-side via terminal Sw. Terminal Bst is connected to one end of capacitor C5 and the cathode of diode D1 for preventing reverse current. Terminal Sw is connected to the other end of capacitor C5. Additionally, the anode of diode D1 is connected to terminal Gvd. Furthermore, terminal Gvd is supplied with a voltage signal Vm, which is, for example, a 7.5V DC voltage output from a power supply circuit (not shown). That is, the anode of diode D1 is supplied with the voltage signal Vm. Therefore, the potential difference between terminal Bst and terminal Sw is approximately equal to the voltage value of the voltage signal Vm. As a result, the gate driver 521 generates an amplified control signal Hgd based on the input modulation signal Ms, whose voltage value relative to terminal Sw is increased by an amount corresponding to the voltage value of the voltage signal Vm, and outputs it from terminal Hdr.

[0071] Gate driver 522 operates at a lower potential than gate driver 521. Gate driver 522 generates an amplified control signal Lgd by level shifting the signal after the logic level of the modulation signal Ms output from comparator 514 is inverted by inverter 515, and outputs it from terminal Ldr.

[0072] Specifically, the high-order side of the power supply voltage of the gate driver 522 is supplied with a voltage signal Vm, and the low-order side is supplied with a ground potential via the terminal Gnd. Furthermore, the gate driver 522 outputs an amplified control signal Lgd from the terminal Ldr, based on the signal obtained by inverting the logic level of the input modulation signal Ms, with a voltage value increased relative to the terminal Gnd by an amount corresponding to the voltage value of the voltage signal Vm. Here, the ground potential refers to the reference potential of the drive circuit 50, for example, 0V.

[0073] The amplifier circuit 550 includes transistor M1 and transistor M2.

[0074] Transistor M1 is a surface-mount FET (Field Effect Transistor). The drain of transistor M1 is supplied with a voltage signal VHV as the power supply voltage for the amplifier circuit 550. This voltage signal VHV is, for example, a 42V DC voltage. Furthermore, the gate of transistor M1 is electrically connected to one end of resistor R1, and the other end of resistor R1 is electrically connected to the terminal Hdr of integrated circuit 500. That is, the gate of transistor M1 is supplied with the amplification control signal Hgd. Additionally, the source of transistor M1 is electrically connected to the terminal Sw of integrated circuit 500.

[0075] Transistor M2 is a surface-mount FET. The drain of transistor M2 is electrically connected to terminal Sw of integrated circuit 500. That is, the drain of transistor M2 is electrically connected to the source of transistor M1. The gate of transistor M2 is electrically connected to one end of resistor R2, and the other end of resistor R2 is electrically connected to terminal Ldr of integrated circuit 500. In other words, the gate of transistor M2 receives an amplified control signal Lgd. Additionally, the source of transistor M2 is supplied with a ground potential.

[0076] Furthermore, when the drain and source of transistor M1 are controlled to be non-conductive, and the drain and source of transistor M2 are controlled to be conductive, the potential of the node connected to terminal Sw becomes the ground potential. Therefore, terminal Bst is supplied with the voltage signal Vm. On the other hand, when the drain and source of transistor M1 are controlled to be conductive, and the drain and source of transistor M2 are controlled to be non-conductive, the potential of the node connected to terminal Sw becomes the voltage value of the voltage signal VHV. Therefore, terminal Bst is supplied with the voltage of the sum of the voltage values ​​of voltage signals VHV and Vm. That is, the gate driver 521 driving transistor M1 uses capacitor C5 as a floating power source, and according to the operation of transistors M1 and M2, changes the potential of terminal Sw to ground potential or voltage value of voltage signal VHV, thereby generating an amplified control signal Hgd with L level being the voltage value of voltage signal VHV and H level being the sum of voltage values ​​of voltage signal VHV and voltage signal Vm, and outputs it to the gate of transistor M1.

[0077] On the other hand, the gate driver 522 that drives transistor M2 generates an amplified control signal Lgd with L level being ground potential and H level being the voltage value of voltage signal Vm, independent of the operation of transistors M1 and M2, and outputs it to the gate of transistor M2.

[0078] The amplifier circuit 550 configured as described above generates an amplified modulation signal AMs at the junction of the source of transistor M1 and the drain of transistor M2. This amplified modulation signal AMs is the signal obtained by amplifying the modulation signal Ms based on the voltage signal VHV. Furthermore, the amplifier circuit 550 outputs the generated amplified modulation signal AMs to the demodulation circuit 560.

[0079] Here, a capacitor C7 is provided on the transmission path of the voltage signal VHV of the input amplifier circuit 550. Specifically, one end of the capacitor C7 is electrically connected to the transmission path of the voltage signal VHV and the drain of the transistor M1, while the other end of the capacitor C7 is supplied with a ground potential. This reduces the possibility of voltage value fluctuations in the voltage signal VHV of the input amplifier circuit 550, and also reduces the possibility of noise superimposed on the voltage signal VHV. As a result, the waveform accuracy of the amplified modulation signal AMs output by the amplifier circuit 550 is improved. Therefore, a high-voltage and large-capacity electrolytic capacitor is used. Furthermore, the capacitor C7 can be configured to correspond to one drive circuit 50 or multiple drive circuits 50.

[0080] The demodulation circuit 560 demodulates the amplified modulation signal AMs output from the amplifier circuit 550 to generate a drive signal COM, which is then output from the drive circuit 50. The demodulation circuit 560 includes an inductor L1 and a capacitor C1. One end of the inductor L1 is connected to one end of the capacitor C1. The other end of the inductor L1 is fed with the amplified modulation signal AMs. Additionally, the other end of the capacitor C1 is supplied with a ground potential. That is, in the demodulation circuit 560, the inductor L1 and capacitor C1 constitute a low-pass filter. Furthermore, the demodulation circuit 560 demodulates the amplified modulation signal AMs by smoothing it using this low-pass filter and outputs the demodulated signal as the drive signal COM. In other words, the drive circuit 50 outputs the drive signal COM from one end of the inductor L1 and one end of the capacitor C1 included in the demodulation circuit 560.

[0081] The feedback circuit 570 includes resistors R3 and R4. One end of resistor R3 is supplied with the drive signal COM, and the other end is connected to terminal Vfb and one end of resistor R4. The other end of resistor R4 is supplied with the voltage signal VHV. Thus, the drive signal COM, after passing through the feedback circuit 570, is fed back to terminal Vfb in a state pulled up by the voltage value of the voltage signal VHV.

[0082] Feedback circuit 572 includes capacitors C2, C3, and C4, and resistors R5 and R6. One end of capacitor C2 is supplied with the drive signal COM, and the other end is connected to one end of resistor R5 and one end of resistor R6. The other end of resistor R5 is supplied with ground potential. Thus, capacitor C2 and resistor R5 function as a high-pass filter. Additionally, the other end of resistor R6 is connected to one end of capacitor C4 and one end of capacitor C3. The other end of capacitor C3 is supplied with ground potential. Thus, resistor R6 and capacitor C3 function as a low-pass filter. In other words, feedback circuit 572 includes a high-pass filter and a low-pass filter, and functions as a band-pass filter that allows signals containing a specified frequency band in the drive signal COM to pass through.

[0083] Furthermore, the other end of capacitor C4 is connected to terminal Ifb of integrated circuit 500. Thus, the DC component of the high-frequency component of the drive signal COM, which passes through the feedback circuit 572 (which functions as a bandpass filter), is cut off and fed back to terminal Ifb.

[0084] The drive signal COM is a smoothed signal obtained by demodulation circuit 560 after amplifying and modulating the signal AMs based on the fundamental drive signal dO. Furthermore, the drive signal COM is fed back to adder 512 after being integrated and subtracted via terminal Vfb. Thus, the drive circuit 50 self-oscillates at a frequency determined by the feedback delay and the feedback transfer function. However, the feedback path via terminal Vfb has a large delay; therefore, feedback via terminal Vfb alone is sometimes insufficient to raise the self-oscillation frequency to a level that adequately ensures the accuracy of the drive signal COM. Therefore, by providing a separate path for the high-frequency components of the drive signal COM via terminal Ifb, compared to the path via terminal Ifb, the delay from the perspective of the entire circuit is reduced. Thus, compared to the absence of a path via terminal Ifb, the frequency of the voltage signal Os can be raised to a level that adequately ensures the accuracy of the drive signal COM.

[0085] As described above, the drive circuit 50 generates a drive signal COM by performing a digital-to-analog conversion on the input basic drive signal dO, followed by a D-level amplification of the analog signal, and outputs the generated drive signal COM. That is, the drive circuit 50 includes a D-level amplification circuit, and the printhead 20 receives the drive signal COM output by the drive circuit 50 including the D-level amplification circuit and ejects liquid.

[0086] 4. Composition of the drive signal selection circuit

[0087] Next, the configuration and operation of the drive signal selection circuit 200 will be explained. As described above, the drive signal selection circuit 200 generates a drive signal VOUT by selecting or not selecting the signal waveform of the drive signal COM, and outputs it to one end of the piezoelectric element 60.

[0088] Figure 4 This is a diagram showing the configuration of the drive signal selection circuit 200. (See diagram for example.) Figure 4 As shown, the drive signal selection circuit 200 has a selection control circuit 210 and selection circuits 230[1] to 230[m] corresponding to the piezoelectric elements 60[1] to 60[m] respectively.

[0089] The selection control circuit 210 receives the input clock signal SCK, latch signal LAT, conversion signal CH, and head control signal DI. The selection control circuit 210 generates selection signals S[1]~S[m] based on the input clock signal SCK, latch signal LAT, conversion signal CH, and head control signal DI. These selection signals S[1]~S[m] are used to switch whether the signal waveform contained in the drive signal COM is output as the drive signal VOUT. The selection signals S[1]~S[m] generated by the selection control circuit 210 are input to the corresponding selection circuits 230[1]~230[m]. The selection circuits 230[1]~230[m] generate drive signals VOUT[1]~VOUT[m] corresponding to the piezoelectric elements 60[1]~60[m] by selecting or not selecting the signal waveform of the drive signal COM according to the input selection signals S[1]~S[m], and output them to the corresponding piezoelectric elements 60[1]~60[m]. Here, the selection circuits 230[1] to 230[m] all have the same configuration, and the selection circuits 230[1] to 230[m] corresponding to the piezoelectric element 60 in the piezoelectric element 60[1] to 60[m] are referred to as selection circuit 230. At this time, the explanation is based on the selection circuit 230 selecting or not selecting the signal waveform of the drive signal COM according to the selection signal S in the selection signal S[1] to S[m].

[0090] When describing the operation of the selection control circuit 210 in detail, a summary of the latch signal LAT, the conversion signal CH, the clock signal SCK, and the head control signal DI input to the selection control circuit 210 will be provided. Figure 5 This is a diagram used to illustrate the relationship between the latch signal LAT, the conversion signal CH, the clock signal SCK, the head control signal DI, and the selection signal S.

[0091] The latch signal LAT is a pulse signal representing the scanning position of the printhead 20 based on the output of the linear encoder 90, defining the period tp during which the printhead 20 forms a dot on the medium P. The conversion signal CH is a pulse signal that specifies the timing for switching whether to supply the drive signal COM containing the signal waveform to the piezoelectric element 60, and divides the period tp into periods t1, t2, and t3. The drive signal selection circuit 200 generates a drive signal VOUT by selecting or not selecting the signal waveform contained in the drive signal COM during each of the periods t1, t2, and t3 obtained by dividing the period tp defined by the latch signal LAT using the conversion signal CH, and outputs it to the piezoelectric element 60.

[0092] In addition, the head control signal DI serially includes an ejection control signal SI and a waveform selection signal SP. The ejection control signal SI independently specifies the amount of ink ejected under the drive of the piezoelectric element 60[1] to 60[m] for each piezoelectric element 60. In addition, the waveform selection signal SP specifies the relationship between the logic level of the selection signal S output in each period t1, t2, t3 and the ejection control signal SI.

[0093] Moreover, such as Figure 5 As shown, the head control signal DI is input to the selection control circuit 210 synchronously with the clock signal SCK during the period tp before the rise of the latch signal LAT. At this time, the head control signal DI input to the selection control circuit 210 is held in the registers corresponding to the piezoelectric elements 60[1] to 60[m]. Moreover, the head control signal DI held in the register is latched together with the rising edge of the latch signal LAT. That is, at the beginning of the period tp, the head control signal DI held in the register is latched together. The selection control circuit 210 generates a selection signal S according to the head control signal DI latched together and corresponding to the periods t1, t2, and t3 in the period tp after the rise of the latch signal LAT, and outputs it to the selection circuit 230.

[0094] Here, the head control signal DI, which includes the ejection control signal SI and the waveform selection signal SP, will be explained in detail. Figure 6 This is a diagram illustrating an example of the data structure of the head control signal DI. For example... Figure 6 As shown, the head control signal DI includes the ejection control signal SI and the waveform selection signal SP.

[0095] The ejection control signal SI is a signal that specifies the amount of ink ejected under the drive of the piezoelectric element 60, and includes upper ejection data SIH and lower ejection data SIL. That is, in the ejection control signal SI, there are two bits of data corresponding to the piezoelectric elements 60[1] to 60[m], namely the upper ejection data SIH and the lower ejection data SIL for controlling the drive of the piezoelectric element 60.

[0096] Specifically, the ejection control signal SI serially includes m-bit upper ejection data SIH corresponding to piezoelectric element 60[1] to 60[m] in the order of upper ejection data SIH corresponding to piezoelectric element 60[m], upper ejection data SIH corresponding to piezoelectric element 60[m-1], ..., upper ejection data SIH corresponding to piezoelectric element 60[1]. Immediately following the upper ejection data SIH, the lower ejection data SIL corresponding to piezoelectric element 60[m], lower ejection data SIL corresponding to piezoelectric element 60[m-1], ..., lower ejection data SIL corresponding to piezoelectric element 60[1] serially includes m-bit lower ejection data SIL corresponding to piezoelectric element 60[1] to 60[m]. That is, the ejection control signal SI is a 2m-bit signal that serially includes m bits of upper ejection data SIH corresponding to piezoelectric elements 60[m] to 60[1] and m bits of lower ejection data SIL corresponding to piezoelectric elements 60[m] to 60[1]. Moreover, the amount of ink ejected under the drive of piezoelectric element 60[i] (i is any one of 1 to m) is determined by the two bits of the upper ejection data SIH corresponding to piezoelectric element 60[i] and the lower ejection data SIL corresponding to piezoelectric element 60[i].

[0097] In the following description, the upper ejection data SIH corresponding to the piezoelectric element 60[i] is sometimes referred to as the upper ejection data SIHi, and the lower ejection data SIL corresponding to the piezoelectric element 60[i] is sometimes referred to as the lower ejection data SILi. Furthermore, in the following description, the upper ejection data SIH and the lower ejection data SIL corresponding to the piezoelectric element 60 are sometimes collectively referred to as ejection data [SIH, SIL], and the upper ejection data SIHi and the lower ejection data SILi corresponding to the piezoelectric element 60[i] are sometimes collectively referred to as ejection data [SIHi, SILi]. That is, the amount of ink ejected under the drive of the piezoelectric element 60[i] is defined by the ejection data [SIHi, SILi].

[0098] The waveform selection signal SP is used to define the drive pattern of the piezoelectric element 60 corresponding to the ejection data [SIH, SIL] during each of the periods t1, t2, and t3, and to define the logic level of the selection signal S output during each of the periods t1, t2, and t3 corresponding to the ejection data [SIH, SIL]. In this embodiment, the waveform selection signal SP is a 12-bit signal containing setting information SP00 to SP03, SP10 to SP13, and SP20 to SP23.

[0099] Specifically, the waveform selection signal SP serially includes setting information SP00~SP03, setting information SP10~SP13, and setting information SP20~SP23 in the order of setting information SP23, SP22, SP21, SP20, SP13, SP12, SP11, SP10, SP03, SP02, SP01, and SP00. Among them, setting information SP00~SP03 specifies the driving pattern of piezoelectric element 60 within the period t1 determined by the ejection data [SIH, SIL], setting information SP10~SP13 specifies the driving pattern of piezoelectric element 60 within the period t2 determined by the ejection data [SIH, SIL], and setting information SP20~SP23 specifies the driving pattern of piezoelectric element 60 within the period t3 determined by the ejection data [SIH, SIL]. Furthermore, the waveform selection signal SP is not limited to a 12-bit signal. It can be a signal of 12 bits or more, or a signal of less than 12 bits, depending on the number of periods divided by the conversion signal CH of the period tp, or the number of drive patterns of the piezoelectric element 60 specified by the ejection control signal SI.

[0100] return Figure 4 The selection control circuit 210 includes a control logic circuit 260 and selection signal output sections 270[1] to 270[m] corresponding to the piezoelectric elements 60[1] to 60[m]. Furthermore, at a timing specified by the input latch signal LAT and the conversion signal CH, the selection control circuit 210 generates selection signals S[1] to S[m] corresponding to the piezoelectric elements 60[1] to 60[m] according to the head control signal DI transmitted synchronously with the clock signal SCK, and outputs them to the corresponding selection circuits 230[1] to 230[m].

[0101] The control logic circuit 260 includes an SP register group 261 and a selection control signal generation unit 262. The SP register group 261 includes multiple registers connected in series and forms a so-called shift register that sequentially transmits the head control signal DI, which is input synchronously with the clock signal SCK, to the registers of the next stage. Moreover, when the clock signal SCK is stopped, the SP register group 261 retains the setting information SP00 to SP23 contained in the waveform selection signal SP of the head control signal DI.

[0102] The selection control signal generation unit 262 latches the setting information SP00 to SP23 in the SP register group 261 at the rising edge of the latch signal LAT. Furthermore, the selection control signal generation unit 262 generates selection control signals Q0, Q1, and Q2 by translating the latched setting information SP00 to SP23, and outputs them to the decoders 226 in the selection signal output units 270[1] to 270[m]. Selection control signal Q0 includes setting information SP00, SP01, SP02, and SP03, and specifies the logic level of the selection signal S output from the selection control circuit 210 during period t1. Selection control signal Q1 includes setting information SP10, SP11, SP12, and SP13, and specifies the logic level of the selection signal S output from the selection control circuit 210 during period t2. Selection control signal Q2 includes setting information SP20, SP21, SP22, and SP23, and specifies the logic level of the selection signal S output from the selection control circuit 210 during period t3. In the following description, the selection control signal Q0 containing setting information SP00, SP01, SP02, SP03 is sometimes referred to as selection control signal Q0[SP00, SP01, SP02, SP03], the selection control signal Q1 containing setting information SP10, SP11, SP12, SP13 is sometimes referred to as selection control signal Q1[SP10, SP11, SP12, SP13], and the selection control signal Q2 containing setting information SP20, SP21, SP22, SP23 is sometimes referred to as selection control signal Q2[SP20, SP21, SP22, SP23].

[0103] The select signal output units 270[1] to 270[m] respectively have a first register 222a, a second register 222b, a first latch circuit 224a, a second latch circuit 224b and a decoder 226.

[0104] The second register 222b contained in each of the selection signal output sections 270[1] to 270[m] is serially connected to the stage following the SP register group 261 containing multiple registers, and the first register 222a contained in each of the selection signal output sections 270[1] to 270[m] is serially connected to the stage following the m serially connected second registers 222b.

[0105] Specifically, the second register 222b contained in the selection signal output section 270[1] is connected to the stage following the SP register group 261. The second register 222b contained in the selection signal output section 270[1] is sequentially connected in series with the second register 222b contained in the selection signal output section 270[2], the second register 222b contained in the selection signal output section 270[3], ..., the second register 222b contained in the selection signal output section 270[m]. Moreover, the first register 222a contained in the selection signal output section 270[1] is connected to the stage following the second register 222b contained in the selection signal output section 270[m]. In addition, the first register 222a contained in the selection signal output section 270[2], the first register 222a contained in the selection signal output section 270[3], ..., the first register 222a contained in the selection signal output section 270[m] is sequentially connected in series with the stage following the first register 222a contained in the selection signal output section 270[1].

[0106] That is, the SP register group 261, the m second registers 222b included in each of the selection signal output sections 270[1] to 270[m], and the m first registers 222a included in each of the selection signal output sections 270[1] to 270[m] constitute a shift register. Moreover, the head control signal DI input to the SP register group 261 is transmitted to the next stage synchronously with the clock signal SCK in the order of the m second registers 222b included in each of the selection signal output sections 270[1] to 270[m] and the m first registers 222a included in each of the selection signal output sections 270[1] to 270[m]. Then, by stopping the supply of clock signal SCK, the lower bit ejection data SILi corresponding to the piezoelectric element 60[i] is held in the second register 222b included in the selection signal output section 270[i], and the upper bit ejection data SIHi corresponding to the piezoelectric element 60[i] is held in the first register 222a included in the selection signal output section 270[i].

[0107] The upper bit ejected data SIH held in the first register 222a of each of the selection signal output units 270[1] to 270[m] is latched by the corresponding first latch circuit 224a on the rising edge of the latch signal LAT, and the lower bit ejected data SIL held in the second register 222b of each of the selection signal output units 270[1] to 270[m] is latched by the corresponding second latch circuit 224b on the rising edge of the latch signal LAT. Moreover, the first latch circuit 224a outputs the latched upper bit ejected data SIH as latched data LTa to the decoder 226, and the second latch circuit 224b outputs the latched lower bit ejected data SIL as latched data LTb to the decoder 226.

[0108] In the following description, the latched data LTa output by the first latch circuit 224a of the selection signal output unit 270[i] is sometimes referred to as latched data LTai, and the latched data LTb output by the second latch circuit 224b of the selection signal output unit 270[i] is sometimes referred to as latched data LTbi. In addition, the latched data LTa and LTb are sometimes collectively referred to as latched data [LTa, LTb], and the latched data LTai and LTbi corresponding to the selection signal output unit 270[i] are sometimes collectively referred to as latched data [LTai, LTbi].

[0109] The selection control signals Q0[SP00, SP01, SP02, SP03], Q1[SP10, SP11, SP12, SP13] and Q2[SP20, SP21, SP22, SP23] output by the selection control signal generation unit 262 are commonly input into the decoder 226 of each of the selection signal output units 270[1] to 270[m], and are input into the latched data [LTa, LTb] output by the corresponding first latch circuit 224a and second latch circuit 224b. That is, the selection signal output unit 270[i] has a decoder 226 that receives selection control signals Q0[SP00, SP01, SP02, SP03], selection control signals Q1[SP10, SP11, SP12, SP13], and selection control signals Q2[SP20, SP21, SP22, SP23], as well as latched data [LTai, LTbi] corresponding to the ejected data [SIHi, SILi]. Furthermore, the decoder 226 of the selection signal output unit 270[i] generates a selection signal S[i] by decoding the latched data [LTai, LTbi] according to the selection control signals Q0, Q1, and Q2, and outputs it to the selection circuit 230[i].

[0110] Figure 7 This is a diagram showing the decoded content of decoder 226 based on the selection control signals Q0, Q1, and Q2. (See diagram for example.) Figure 7 As shown, the decoder 226 outputs a selection signal S with a logic level specified by the selection control signal Q0 [SP00, SP01, SP02, SP03] during period t1, outputs a selection signal S with a logic level specified by the selection control signal Q1 [SP10, SP11, SP12, SP13] during period t2, and outputs a selection signal S with a logic level specified by the selection control signal Q2 [SP20, SP21, SP22, SP23] during period t3.

[0111] Specifically, when latched data [LTa, LTb] = [1, 1] is input into decoder 226, decoder 226, according to the content specified by selection control signals Q0, Q1, and Q2, outputs the logic level of setting information SP00 as selection signal S during period t1, the logic level of setting information SP10 as selection signal S during period t2, and the logic level of setting information SP20 as selection signal S during period t3. Similarly, when latched data [LTa, LTb] = [1, 0] is input into decoder 226, decoder 226, according to the content specified by selection control signals Q0, Q1, and Q2, outputs the logic level of setting information SP01 as selection signal S during period t1, the logic level of setting information SP11 as selection signal S during period t2, and the logic level of setting information SP21 as selection signal S during period t3. Similarly, when latched data [LTa, LTb] = [0, 1] is input into decoder 226, decoder 226, according to the content specified by selection control signals Q0, Q1, and Q2, outputs the logic level of setting information SP02 as selection signal S during period t1, the logic level of setting information SP12 as selection signal S during period t2, and the logic level of setting information SP22 as selection signal S during period t3. Similarly, when latched data [LTa, LTb] = [0, 0] is input into decoder 226, decoder 226, according to the content specified by selection control signals Q0, Q1, and Q2, outputs the logic level of setting information SP03 as selection signal S during period t1, the logic level of setting information SP13 as selection signal S during period t2, and the logic level of setting information SP23 as selection signal S during period t3.

[0112] As described above, the selection control circuit 210 outputs selection signals S[1]~S[m] based on the clock signal SCK, latch signal LAT, conversion signal CH and head control signal DI. These selection signals S[1]~S[m] are used to control the state of the selection circuits 230[1]~230[m] corresponding to the piezoelectric elements 60[1]~60[m].

[0113] Next, the configuration of selection circuits 230[1] to 230[m] will be explained. Here, selection circuits 230[1] to 230[m] all have the same configuration. Therefore, when it is not necessary to distinguish between selection circuits 230[1] to 230[m], they are sometimes simply referred to as selection circuit 230. Moreover, the explanation will focus on the selection signal S in selection signals S[1] to S[m] being input into selection circuit 230.

[0114] Figure 8This is a diagram showing the configuration of the selection circuit 230 corresponding to the piezoelectric element 60. (For example...) Figure 8 As shown, the selection circuit 230 has an inverter 232 and a transmission gate 234 that function as a NOT circuit.

[0115] The selection signal S output by the selection control circuit 210 is input to the positive control terminal (not marked with a circle) of the transmission gate 234. Conversely, it is logically inverted by the inverter 232 and input to the negative control terminal (marked with a circle) of the transmission gate 234. Furthermore, a drive signal COM is supplied to the input terminal of the transmission gate 234. Specifically, the transmission gate 234 conducts between its input and output terminals when the input selection signal S is at a high level (H), and de-conducts between its input and output terminals when the input selection signal S is at a low level (L). Moreover, a drive signal VOUT is output from the output terminal of the transmission gate 234.

[0116] As described above, the drive signal selection circuit 200 in this embodiment selects or does not select the signal waveform of the drive signal COM according to the input clock signal SCK, latch signal LAT, conversion signal CH and head control signal DI, thereby generating drive signals VOUT[1] to VOUT[m] corresponding to the piezoelectric elements 60[1] to 60[m] respectively, and outputs them to the corresponding piezoelectric elements 60[1] to 60[m].

[0117] Here, an example of the specific operation of the drive signal selection circuit 200 will be described. The drive signal selection circuit 200 generates a drive signal VOUT by selecting or deselecting the signal waveform of the drive signal COM, and outputs it to one end of the piezoelectric element 60. Therefore, when describing an example of the specific operation of the drive signal selection circuit 200, a specific example of the signal waveform of the drive signal COM input to the drive signal selection circuit 200 will be described.

[0118] Figure 9 This is a diagram illustrating an example of the signal waveform of the drive signal COM. (Example) Figure 9 As shown, the drive signal COM is a signal containing a signal waveform that makes the trapezoidal waveforms Adp, Bdp, and Cdp continuous. The trapezoidal waveform Adp is configured within the period t1 from the rise of the latch signal LAT to the rise of the conversion signal CH, the trapezoidal waveform Bdp is configured within the period t2 from the rise of the conversion signal CH to the next rise of the conversion signal CH, and the trapezoidal waveform Cdp is configured within the period t3 from the rise of the conversion signal CH to the rise of the latch signal LAT.

[0119] The trapezoidal waveform Adp is a signal waveform that drives the piezoelectric element 60 to eject a predetermined amount of ink from the corresponding nozzle when supplied to it. The trapezoidal waveform Bdp is a signal waveform that drives the piezoelectric element 60 to eject a smaller amount of ink from the corresponding nozzle when supplied to it. The trapezoidal waveform Cdp is a signal waveform that drives the piezoelectric element 60 to not eject ink from the corresponding nozzle even when supplied to it. Here, the trapezoidal waveform Cdp is a signal waveform used to moderately vibrate the ink near the nozzle opening to prevent the ink viscosity from increasing. In the following description, the action of vibrating the ink near the nozzle opening when the trapezoidal waveform Cdp is supplied to the piezoelectric element 60 is sometimes referred to as micro-vibration. In addition, in the following description, the amount of ink ejected when the trapezoidal waveform Adp is supplied to the piezoelectric element 60 is sometimes referred to as a large amount, and the amount of ink ejected when the trapezoidal waveform Bdp is supplied to the piezoelectric element 60 is sometimes referred to as a small amount.

[0120] Furthermore, the start and end timing voltage values ​​of the trapezoidal waveforms Adp, Bdp, and Cdp are all the same: voltage Vc. That is, the trapezoidal waveforms Adp, Bdp, and Cdp begin and end with voltage Vc, respectively. Moreover, the period tp formed by these periods t1, t2, and t3 is equivalent to the point formation period for forming a new point on the dielectric P.

[0121] Figure 10 This diagram illustrates an example of the head control signal DI, which is input to the drive signal selection circuit 200. Here, the ejection control signal SI included in the head control signal DI specifies the amount of ink ejected under the drive of the piezoelectric element 60. Therefore, the logic level of the ejection control signal SI changes appropriately during printing when the liquid ejection device 1 ejects ink to form the desired image on the medium P. That is, the logic level of the ejection data [SIH, SIL] included in the ejection control signal SI changes to either 0 or 1 depending on the amount of ink ejected. In other words, the logic level of the ejection data [SIH, SIL] included in the ejection control signal SI changes periodically by tp according to the image formed on the medium P. Therefore, in Figure 10 The diagram only shows the specific logic level of the waveform selection signal SP, while omitting the actual logic level of the waveform selection signal SP.

[0122] like Figure 10As shown, the drive signal selection circuit 200 receives a header control signal DI containing setting information SP00, SP01, SP02, SP03, SP10, SP11, SP12, SP13, SP20, SP21, SP22, and SP23, which are respectively "1", "0", "0", "0", "0", "1", "0", "0", "0", "1", "0", "0", "1", and "0". Therefore, the selection control signal generation unit 262 included in the control logic circuit 260 generates selection control signals Q0[SP00, SP01, SP02, SP03] = [1, 0, 0, 0], selection control signals Q1[SP10, SP11, SP12, SP13] = [0, 1, 0, 0], and selection control signals Q2[SP20, SP21, SP22, SP23] = [0, 0, 1, 0] based on the waveform selection signals SP, and outputs them to the decoder 226.

[0123] Figure 11 This diagram illustrates a specific example of the decoding content of the decoder 226 when a head control signal DI containing the aforementioned waveform selection signal SP is input to the drive signal selection circuit 200. Furthermore, the decoder 226 of this embodiment will be described as outputting a selection signal S at level H when the logic level of the corresponding setting information SP23-SP20, SP13-SP10, and SP03-SP00 is "1", and outputting a selection signal S at level L when the logic level of the corresponding setting information SP23-SP20, SP13-SP10, and SP03-SP00 is "0".

[0124] like Figure 11 As shown, when latched data [LTa, LTb] = [1, 1] corresponding to the ejected data [SIH, SIL] = [1, 1] is input to decoder 226, decoder 226 outputs selection signal S that is at H, L, L level during periods t1, t2, and t3. Furthermore, when latched data [LTa, LTb] = [1, 0] corresponding to the ejected data [SIH, SIL] = [1, 0] is input to decoder 226, decoder 226 outputs selection signal S that is at L, H, L level during periods t1, t2, and t3. Additionally, when latched data [LTa, LTb] = [0, 1] corresponding to the ejected data [SIH, SIL] = [0, 1] is input to decoder 226, decoder 226 outputs selection signal S that is at L, L, H level during periods t1, t2, and t3. Additionally, when inputting latched data [LTa, LTb] = [0, 0] corresponding to the ejected data [SIH, SIL] = [0, 0] into the decoder 226, the decoder 226 outputs a selection signal S that is at level L, L, L during the periods t1, t2, and t3.

[0125] Figure 12It means that it was supplied Figure 11 The diagram shows the drive signal VOUT output from the selection circuit 230 when the selection signal S is shown.

[0126] like Figure 12 As shown, when latched data [LTa, LTb] = [1, 1] is input to decoder 226, the logic level of selection signal S is H level during period t1, L level during period t2, and L level during period t3. Therefore, the input and output terminals of selection circuit 230 are connected during period t1, not connected during period t2, and not connected during period t3. As a result, selection circuit 230 outputs a drive signal VOUT that is a trapezoidal waveform Adp during period t1, a constant voltage Vc during period t2, and a constant voltage Vc during period t3.

[0127] At this time, driven by the piezoelectric element 60, a large amount of ink is ejected during period t1, and no ink is ejected during period t2 and period t3. Therefore, a large amount of ink falls onto the medium P, thus forming large dots on the medium P.

[0128] Furthermore, when latched data [LTa, LTb] = [1, 0] is input to decoder 226, the logic level of selection signal S is L during period t1, H during period t2, and L during period t3. Therefore, the input and output terminals of selection circuit 230 are not connected during period t1, are connected during period t2, and are not connected during period t3. As a result, selection circuit 230 outputs a drive signal VOUT that is constant at voltage Vc during period t1, becomes a trapezoidal waveform Bdp during period t2, and is constant at voltage Vc during period t3.

[0129] At this time, driven by the piezoelectric element 60, no ink is ejected during period t1, a small amount of ink is ejected during period t2, and no ink is ejected during period t3. Therefore, a small amount of ink falls onto the medium P, thus forming small dots on the medium P.

[0130] Furthermore, when latched data [LTa, LTb] = [0, 1] is input to decoder 226, the logic level of selection signal S becomes L level during period t1, L level during period t2, and H level during period t3. Therefore, the input and output terminals of selection circuit 230 are not connected during period t1, not connected during period t2, and connected during period t3. As a result, selection circuit 230 outputs a drive signal VOUT that is constant at voltage Vc during period t1, constant at voltage Vc during period t2, and becomes a trapezoidal waveform Cdp during period t3.

[0131] At this time, driven by the piezoelectric element 60, no ink is ejected during period t1, no ink is ejected during period t2, and no ink is ejected during period t3. Therefore, no ink settles on the medium P, and thus no dots are formed on the medium P, resulting in micro-vibration.

[0132] Furthermore, when latched data [LTa, LTb] = [0, 0] is input to decoder 226, the logic level of selection signal S becomes low during period t1, low during period t2, and low during period t3. Therefore, the input and output terminals of selection circuit 230 are not connected during period t1, low during period t2, and low during period t3. As a result, selection circuit 230 outputs a drive signal VOUT that remains constant at voltage Vc during period t1, voltage Vc during period t2, and voltage Vc during period t3. At this time, driven by piezoelectric element 60, no ink is ejected during period t1, no ink is ejected during period t2, and no ink is ejected during period t3. Therefore, no ink settles on medium P, and no dot is formed on medium P. At this time, the ink near the opening of the nozzle corresponding to piezoelectric element 60 also does not vibrate.

[0133] As described above, the ejection module 22 of this embodiment includes multiple piezoelectric elements, and the drive signal selection circuit 200 has multiple selection circuits 230. The selection circuits 230 switch whether to supply a drive signal VOUT based on the drive signal COM to the multiple piezoelectric elements 60 included in the ejection module 22. Furthermore, in the drive signal selection circuit 200, the selection circuit 230 outputs a drive signal VOUT for controlling the circuit to be on during period t1 within the period tp and to be off during periods t2 and t3, thereby forming a large point on the medium P. The selection circuit 230 outputs a drive signal VOUT for controlling the circuit to be on during period t2 within the period tp and to be off during periods t1 and t2, thereby forming a small point on the medium P. The selection circuit 230 outputs a drive signal VOUT for controlling the circuit to be on during period t3 within the period tp and to be off during periods t1 and t2, thereby not forming a point on the medium P but performing micro-vibration. The selection circuit 230 outputs a drive signal VOUT for controlling the circuit to be on during period t3 within the period tp and to be off during periods t1 and t2, thereby not forming a point on the medium P but performing micro-vibration. The selection circuit 230 outputs a drive signal VOUT for controlling the circuit to be off during all periods t1 to t3 within the period tp, thereby not forming a point on the medium P and not performing micro-vibration.

[0134] Here, the drive signal VOUT output by the drive signal selection circuit 200 makes the signal waveform of any one of the trapezoidal waveforms Adp, Bdp, and Cdp included in the drive signal COM continuous with the signal waveform of the voltage Vc maintained by the capacitive component of the piezoelectric element 60 supplied with the drive signal VOUT. That is, the drive signal VOUT output by the drive signal selection circuit 200 is synonymous with the drive signal VOUT supplied to the piezoelectric element 60.

[0135] 5. The composition of the ejection module 22 in the printhead 20

[0136] Next, the structure of the ejection module 22 of the printhead 20 will be described. Figure 13 This is an exploded perspective view showing the structure of the ejection module 22. Figure 14 This is a top view of the ejection module 22. Figure 15 It means Figure 14 The sectional view of section IV-IV shown. Figure 16 yes Figure 15 Detailed diagrams of the main parts, Figure 17 It means Figure 14 The diagram shows a cross-sectional view along section VI-VI. Furthermore, when describing the structure of the printhead 20, three mutually orthogonal spatial axes X, Y, and Z are illustrated in each figure. In this embodiment, the directions along these axes are referred to as the X-axis direction, Y-axis direction, and Z-axis direction. When the orientation is determined, positive directions are designated as "+", and negative directions as "-". In the direction description, the direction in which the arrow points in each figure is designated as the "+" direction, and the opposite direction of the arrow is designated as the "-" direction. Additionally, the Z-axis direction represents the vertical direction; the +Z direction represents vertically downward, and the -Z direction represents vertically upward. Furthermore, the three spatial axes X, Y, and Z, whose positive and negative directions are not limited, are referred to as the X-axis, Y-axis, and Z-axis.

[0137] like Figure 13 As shown, the ejection module 22 ejects ink in the Z-axis direction, more specifically in the +Z-axis direction. The ejection module 22 includes, as a component, a pressure chamber substrate 310, a connecting plate 315, a nozzle plate 320, a malleable substrate 345, a vibrating plate 350 (described later), a piezoelectric element 60 (described later), a protective substrate 330, a housing component 340, and a wiring substrate 420.

[0138] The pressure chamber substrate 310 is composed of, for example, a silicon substrate, a glass substrate, an SOI substrate, or various ceramic substrates. Figure 14 As shown, two rows of pressure chambers are arranged along the X-axis on the pressure chamber substrate 310. These pressure chamber rows are formed by arranging multiple pressure chambers 312 along the Y-axis. In other words, the ejection module 22 of the printhead 20 has multiple pressure chambers 312, which form multiple pressure chamber rows arranged along the Y-axis. Here, the pressure chamber row located on the +X direction side is sometimes referred to as the first pressure chamber row, and the pressure chamber row separated from the first pressure chamber row in the X-axis direction towards the -X direction is referred to as the second pressure chamber row. Furthermore, Figure 14 This is a top view of the ejection module 22, illustrating the structure around the pressure chamber substrate 310, but omitting the illustrations of the protective substrate 330 and the housing component 340.

[0139] Furthermore, the multiple pressure chambers 312 constituting each pressure chamber row are arranged in a straight line along the Y-axis with their positions being identical in the X-axis direction. The pressure chambers 312 adjacent to each other in the Y-axis direction are... Figure 17 The partition wall 311 is shown. Of course, the arrangement of the pressure chambers 312 is not particularly limited. For example, the arrangement of multiple pressure chambers 312 arranged along the Y-axis can also be a so-called staggered arrangement in which the positions of each pressure chamber 312 are staggered in the X-axis direction every other one.

[0140] Furthermore, the pressure chamber 312 in this embodiment is formed such that, when viewed from above in the +Z direction, its length in the X-axis direction is longer than its length in the Y-axis direction, for example, it is rectangular. Of course, the shape of the pressure chamber 312 when viewed from above in the +Z direction is not particularly limited, and it can also be a parallelogram shape, a polygon shape, a circle shape, an ellipse shape, etc. In addition, the ellipse shape mentioned here refers to a shape that is based on a rectangle and has the two ends of the long side formed as semicircles, including rounded rectangular shapes, ellipse shapes, oval shapes, etc.

[0141] like Figure 13 , Figure 16 As shown, a connecting plate 315, a nozzle plate 320, and a plastic substrate 345 are sequentially stacked on the +Z axis side of the pressure chamber substrate 310.

[0142] The connecting plate 315 is provided with a nozzle connecting channel 316 that connects the pressure chamber 312 and the nozzle 321. Additionally, the connecting plate 315 is provided with a first manifold portion 317 and a second manifold portion 318, which together form part of a manifold 400 that communicates with a common liquid chamber of the plurality of pressure chambers 312. The first manifold portion 317 extends through the connecting plate 315 along the Z-axis direction. The second manifold portion 318 does not extend through the connecting plate 315 along the Z-axis direction, but is instead configured to open on a surface in the +Z-axis direction.

[0143] Furthermore, on the connecting plate 315, a supply connecting channel 319 is provided independently of each pressure chamber 312, communicating with one end of the pressure chamber 312 in the X-axis direction. The supply connecting channel 319 connects the second manifold section 318 to each pressure chamber 312, thereby supplying ink from the manifold 400 to each pressure chamber 312.

[0144] The connecting plate 315 can be made of silicon substrate, glass substrate, SOI substrate, various ceramic substrates, metal substrates, etc. For example, stainless steel substrate can be used as a metal substrate. Furthermore, the connecting plate 315 is preferably made of a material with a coefficient of thermal expansion that is approximately the same as that of the pressure chamber substrate 310. This reduces the possibility of warping on the pressure chamber substrate 310 and the connecting plate 315 due to differences in their coefficients of thermal expansion when the temperature of the pressure chamber substrate 310 and the connecting plate 315 changes.

[0145] The nozzle plate 320 is disposed on the side of the connecting plate 315 opposite to the pressure chamber base plate 310, i.e., on the +Z axis direction side. Nozzles 321 are formed on the nozzle plate 320 and communicate with each pressure chamber 312 via nozzle connecting channels 316.

[0146] In this embodiment, a plurality of nozzles 321 are arranged in a row along the Y-axis direction. Furthermore, on the nozzle plate 320, two separate rows of nozzles 321 are arranged in the X-axis direction. These two rows of nozzles correspond to the first pressure chamber row and the second pressure chamber row, respectively. The plurality of nozzles 321 in each row are arranged in the same position along the X-axis direction. Moreover, the arrangement of the nozzles 321 is not particularly limited. For example, the nozzles 321 arranged along the Y-axis direction may be arranged at positions offset along the X-axis direction, with every other nozzle being one of them.

[0147] The material of the nozzle plate 320 is not particularly limited; for example, silicon substrates, glass substrates, SOI substrates, various ceramic substrates, and metal substrates can be used. Examples of metal substrates include stainless steel substrates. Furthermore, organic materials such as polyimide resin can also be used as the material of the nozzle plate 320. However, it is preferable to use a material with a coefficient of thermal expansion approximately the same as that of the connecting plate 315 for the nozzle plate 320. This reduces the possibility of warping in the nozzle plate 320 and the connecting plate 315 due to differences in their coefficients of thermal expansion when the temperature of the nozzle plate 320 and the connecting plate 315 changes.

[0148] A malleable substrate 345 is disposed together with a nozzle plate 320 on the side of the connecting plate 315 opposite to the pressure chamber substrate 310, i.e., on the +Z axis direction side. The malleable substrate 345 is disposed around the nozzle plate 320 and seals the openings of the first manifold portion 317 and the second manifold portion 318 disposed on the connecting plate 315. The malleable substrate 345 includes a sealing film 346 made of a flexible thin film and a fixing substrate 347 made of a rigid material such as metal. The region of the fixing substrate 347 opposite the manifold 400 becomes an opening 348 that is completely removed in the thickness direction. Therefore, one side of the manifold 400 becomes a malleable portion 349 sealed only by the flexible sealing film 346.

[0149] On the other hand, on the side of the pressure chamber substrate 310 opposite to the nozzle plate 320, i.e., the -Z direction side, a vibrating plate 350 and a piezoelectric element 60 are stacked, which causes the vibrating plate 350 to flex and deform, thereby generating pressure changes in the ink within the pressure chamber 312, as will be described in detail later. In other words, the vibrating plate 350 is positioned relative to the piezoelectric element 60 in the +Z axis direction of the Z axis, and the pressure chamber substrate 310 is positioned relative to the vibrating plate 350 in the +Z axis direction of the Z axis. Furthermore, Figure 15 This is a diagram illustrating the overall structure of the ejection module 22, and a simplified representation of the structure of the piezoelectric element 60.

[0150] On the Z-axis side of the pressure chamber substrate 310, a protective substrate 330 having approximately the same size as the pressure chamber substrate 310 is bonded by an adhesive or the like. The protective substrate 330 has a holding portion 331 that serves as a space for protecting the piezoelectric elements 60. The holding portion 331 is provided independently for each row of piezoelectric elements 60 arranged along the Y-axis, and two are formed in the X-axis direction. Furthermore, a through hole 332 extending along the Z-axis is provided on the protective substrate 330 between the two holding portions 331 arranged along the X-axis.

[0151] Additionally, a housing component 340 is fixed to the protective substrate 330. This housing component 340, together with the pressure chamber substrate 310, forms a manifold 400 that communicates with a plurality of pressure chambers 312. When viewed from above in the Z-axis direction, the housing component 340 has a shape substantially the same as the aforementioned connecting plate 315, and is engaged with both the protective substrate 330 and the aforementioned connecting plate 315.

[0152] Such a housing component 340 has a storage portion 341 on the protective substrate 330 side, which serves as a space capable of accommodating the pressure chamber substrate 310 and the protective substrate 330. This storage portion 341 has an opening area larger than the surface of the protective substrate 330 that engages with the pressure chamber substrate 310. Furthermore, when the pressure chamber substrate 310 and the protective substrate 330 are housed in the storage portion 341, the opening surface on the nozzle plate 320 side of the storage portion 341 is sealed by the connecting plate 315.

[0153] Furthermore, on the housing component 340, third manifold portions 342 are formed on both outer sides of the receiving portion 341 in the X-axis direction. Moreover, a manifold 400 is formed by the first manifold portion 317, the second manifold portion 318, and the third manifold portion 342 provided on the connecting plate 315. The manifold 400 is continuously provided in the entire Y-axis direction, and the supply communication channels 319 connecting each pressure chamber 312 to the manifold 400 are arranged along the Y-axis direction.

[0154] Additionally, the housing component 340 is provided with a supply port 344 that communicates with the manifold 400 and is used to supply ink to each manifold 400. Furthermore, the housing component 340 is provided with a connection port 343 that communicates with the through hole 332 of the protective substrate 330, and the wiring substrate 420 is inserted into the connection port 343.

[0155] In this ejection module 22 of this embodiment, ink stored in the ink container 2 is taken in through the supply port 344, and after the ink fills the interior from the manifold 400 to the nozzle 321, a drive signal VOUT based on the drive signal COM is supplied from the integrated circuit 421, which includes the drive signal selection circuit 200, to each piezoelectric element 60 corresponding to the pressure chamber 312. As a result, the vibrating plate 350 and the piezoelectric element 60 flex and deform together, the pressure in each pressure chamber 312 increases, and ink is ejected from each nozzle 321. Moreover, the printhead 20 is configured by having multiple ejection modules 22 described above.

[0156] Next, the configuration, including the aforementioned vibrating plate 350 and piezoelectric element 60, which is stacked on the -Z-axis side of the pressure chamber substrate 310, will be described in detail. As a configuration stacked on the -Z-axis side of the pressure chamber substrate 310, in addition to the vibrating plate 350 and piezoelectric element 60, the ejection module 22 also includes an independent lead electrode 391, a common lead electrode 392, a measurement lead electrode 393, and a resistance wiring 401.

[0157] like Figures 15 to 17 As shown, the vibrating plate 350 is composed of an elastic membrane 351 and an insulating membrane 352. The elastic membrane 351 is disposed on the pressure chamber substrate 310 side and is made of silicon oxide, while the insulating membrane 352 is disposed on the elastic membrane 351 and is made of zirconium oxide. The liquid flow channels of the pressure chamber 312, etc., are formed by anisotropic etching of the surface from the +Z axis direction side of the pressure chamber substrate 310, and the surface of the liquid flow channels of the pressure chamber 312, etc., in the -Z axis direction direction is composed of the elastic membrane 351.

[0158] Furthermore, the composition of the vibrating plate 350 is not particularly limited. For example, the vibrating plate 350 may be composed of either an elastic membrane 351 or an insulating membrane 352, or it may include other membranes besides the elastic membrane 351 and the insulating membrane 352. Examples of other membrane materials include silicon and silicon nitride.

[0159] The piezoelectric element 60 is an example of a piezoelectric actuator that causes pressure changes in the ink within the pressure chamber 312. This piezoelectric element 60 has a first electrode 360, a piezoelectric body 370, and a second electrode 380 stacked sequentially from the vibrating plate 350 side (+Z-axis direction) towards the -Z-axis direction. In other words, the piezoelectric element 60 includes a first electrode 360, a second electrode 380, and a piezoelectric body 370, with the piezoelectric body 370 disposed between the first electrode 360 ​​and the second electrode 380 in the Z-axis direction where the first electrode 360, the second electrode 380, and the piezoelectric body 370 are stacked.

[0160] Both the first electrode 360 ​​and the second electrode 380 are electrically connected to the wiring substrate 420, and a drive signal VOUT supplied from the drive signal selection circuit 200 included in the integrated circuit 421 mounted on the wiring substrate 420, and a reference voltage signal VBS transmitted in the wiring substrate 420 are supplied to the piezoelectric element 370. The drive signal VOUT, which varies depending on the amount of ink ejected, is supplied to the first electrode 360, while the reference voltage signal VBS, which is constant regardless of the amount of ink ejected, is supplied to the second electrode 380. This creates a potential difference between the first electrode 360 ​​and the second electrode 380, causing the piezoelectric element 370 to deform. That is, by driving the piezoelectric element 60, the vibrating plate 350 deforms or vibrates, causing a change in the volume of the pressure chamber 312, thereby applying pressure to the ink contained in the pressure chamber 312. As a result, ink is ejected from the nozzle 321 via the nozzle communication channel 316. In this case, the amount of change in the volume of the pressure chamber 312 becomes the amount of ink ejected.

[0161] The portion of the piezoelectric element 60 that generates piezoelectric strain when a voltage is applied between the first electrode 360 ​​and the second electrode 380 is called the active portion 410. Conversely, the portion of the piezoelectric element 370 that does not generate piezoelectric strain is called the inactive portion 415. That is, the portion of the piezoelectric element 60 where the piezoelectric element 370 is clamped between the first electrode 360 ​​and the second electrode 380 is the active portion 410, and the portion where the piezoelectric element 370 is not clamped between the first electrode 360 ​​and the second electrode 380 is the inactive portion 415. Furthermore, the portion of the piezoelectric element 60 that displaces in the Z-axis direction when driven is called the flexible portion, and the portion that does not displace in the Z-axis direction is called the non-flexible portion. That is, the portion of the piezoelectric element 60 opposite the pressure chamber 312 in the Z-axis direction is called the flexible portion, and the outer portion of the pressure chamber 312 is called the non-flexible portion. In addition, the active portion 410 is also called the active portion, and the inactive portion 415 is also called the inactive portion.

[0162] Generally, one electrode of the active part 410 is configured as an independent electrode for each active part 410, and the other electrode is configured as a common electrode shared by multiple active parts 410. In this embodiment, the first electrode 360 ​​is configured as an independent electrode, and the second electrode 380 is configured as a common electrode.

[0163] Specifically, the first electrode 360 ​​is disposed on the +Z-axis side of the Z-axis direction relative to the piezoelectric body 370, and is divided for each pressure chamber 312, thereby forming an independent electrode for each active part 410. That is, the first electrode 360 ​​is disposed independently relative to the plurality of pressure chambers 312. The first electrode 360 ​​is formed with a width narrower than the width of the pressure chamber 312 in the Y-axis direction. That is, in the Y-axis direction, the end of the first electrode 360 ​​is located inside the region opposite to the pressure chamber 312.

[0164] Furthermore, the +X direction end 360a and the -X direction end 360b of the first electrode 360 ​​are respectively disposed on the outside of the pressure chamber 312. For example, in the first pressure chamber row, such as Figure 16 As shown, the end 360a of the first electrode 360 ​​is positioned further towards the +X-axis direction than the end 312a of the pressure chamber 312 in the +X-axis direction. The end 360b of the first electrode 360 ​​is positioned further towards the -X-axis direction than the end 312b of the pressure chamber 312 in the -X-axis direction.

[0165] The material of the first electrode 360 ​​is not particularly limited. For example, conductive materials such as metals like platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti), or conductive metal oxides like indium tin oxide (ITO) can be used. Alternatively, multiple materials such as platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti) can be stacked together. In this embodiment, platinum (Pt) is used as the first electrode 360.

[0166] like Figure 14 As shown, the piezoelectric element 370 is continuously arranged along the entire Y-axis direction with a predetermined length in the X-axis direction. That is, the piezoelectric element 370 is continuously arranged along the parallel direction of the pressure chamber 312 with a predetermined thickness. The thickness of the piezoelectric element 370 is not particularly limited and is formed with a thickness of about 1000 nanometers to 4000 nanometers.

[0167] In addition, such as Figure 16 As shown, the length of the piezoelectric element 370 in the X-axis direction is longer than the length of the pressure chamber 312 in the X-axis direction. Therefore, the piezoelectric element 370 extends to the outside of the pressure chamber 312 on both sides in the X-axis direction. In this way, by extending the piezoelectric element 370 to the outside of the pressure chamber 312 in the X-axis direction, the strength of the vibrating plate 350 is improved. Therefore, the possibility of cracks or the like in the vibrating plate 350 or the piezoelectric element 60 when the active part 410 is driven to displace the piezoelectric element 60 can be reduced.

[0168] Additionally, for example in the first pressure chamber row, such as Figure 16As shown, the +X direction end 370a of the piezoelectric body 370 is located on the +X axis direction side, which is further outward than the end 360a of the first electrode 360. That is, the end 360a of the first electrode 360 ​​is covered by the piezoelectric body 370. On the other hand, the -X direction end 370b of the piezoelectric body 370 is located on the +X axis direction side, which is further inward than the end 360b of the first electrode 360, and the end 360b of the first electrode 360 ​​is not covered by the piezoelectric body 370.

[0169] In addition, such as Figure 14 and Figure 17 As shown, grooves 371 are formed on the piezoelectric body 370 corresponding to each partition wall 311, and these grooves 371 are thinner than other areas. In this embodiment, the grooves 371 are formed by completely removing the piezoelectric body 370 in the Z-axis direction. That is, the piezoelectric body 370 having a thinner portion than other areas also includes the case where the piezoelectric body 370 is completely removed in the Z-axis direction. Of course, the piezoelectric body 370 can also be formed thinner than other portions on the bottom surface of the groove 371.

[0170] Furthermore, the length of the groove 371 in the Y-axis direction, that is, the width of the groove 371, is the same as or wider than the width of the partition wall 311. In this embodiment, the width of the groove 371 is wider than the width of the partition wall 311.

[0171] Such a groove 371 is formed so that it appears rectangular when viewed from the -Z axis direction. Of course, the shape of the groove 371 when viewed from the -Z axis direction is not limited to a rectangular shape; it can also be a polygon with more than one pentagon, or a circular or elliptical shape, etc.

[0172] By providing a groove 371 in the piezoelectric element 370, the rigidity of the portion of the vibrating plate 350 that is opposite to the end of the pressure chamber 312 in the Y-axis direction, i.e. the arm of the vibrating plate 350, is suppressed, thereby allowing the piezoelectric element 60 to be displaced more effectively.

[0173] Examples of piezoelectric materials 370 include perovskite-structured crystalline films formed on the first electrode 360 ​​using a highly dielectric ceramic material exhibiting electromechanical conversion properties, or so-called perovskite-type crystals. Materials for the piezoelectric material 370 can include highly dielectric piezoelectric materials such as lead zirconate titanate (PZT) or materials to which metal oxides such as niobium oxide, nickel oxide, or magnesium oxide have been added. Specifically, lead titanate (PbTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), lead zirconate (PbZrO3), lanthanum lead titanate ((Pb,La),TiO3), lanthanum lead zirconate titanate ((Pb,La)(Zr,Ti)O3), or lead zirconate titanate magnesium niobate (Pb(Zr,Ti)(Mg,Nb)O3) can be used. In this embodiment, lead zirconate titanate (PZT) is used as the piezoelectric material 370.

[0174] Furthermore, the material used for the piezoelectric element 370 is not limited to lead-based piezoelectric materials containing lead; lead-free, non-lead-based piezoelectric materials can also be used. Examples of non-lead-based piezoelectric materials include bismuth ferrite ((BiFeO3), abbreviated as "BFO"), barium titanate ((BaTiO3), abbreviated as "BT"), potassium sodium niobate ((K,Na)(NbO3), abbreviated as "KNN"), lithium sodium potassium niobate ((K,Na,Li)(NbO3)), lithium sodium potassium niobate ((K,Na,Li)(Nb,Ta)O3), potassium bismuth potassium titanate ((Bi1 / 2K1 / 2)TiO3, abbreviated as "BKT"), sodium bismuth titanate ((Bi1 / 2Na1 / 2)TiO3, abbreviated as "BNT"), and bismuth manganate (B iMnO3 (abbreviated as "BM"), composite oxides with a perovskite structure containing bismuth, potassium, titanium and iron (x[(BixK1-x)TiO3]-(1-x)[BiFeO3], abbreviated as "BKT-BF"), composite oxides with a perovskite structure containing bismuth, iron, barium and titanium ((1-x)[BiFeO3]-x[BaTiO3], abbreviated as "BFO-BT"), or substances formed by adding metals such as manganese, cobalt, chromium, etc. ((1-x)[Bi(Fe1-yMy)O3]-x[BaTiO3] (M is Mn, CO or Cr)), etc.

[0175] like Figure 14 , Figure 16 as well as Figure 17As shown, the second electrode 380 is disposed on the side opposite to the first electrode 360, i.e., the -Z-axis side, and constitutes a common electrode shared by multiple active parts 410. That is, the second electrode 380 is provided as a common electrode for multiple pressure chambers 312. The second electrode 380 is continuously disposed in the entire Y-axis direction with a predetermined length in the X-axis direction. The second electrode 380 is also disposed on the inner surface of the groove 371, i.e., on the side surface of the groove 371 of the piezoelectric body 370, and on the insulating film 352 that serves as the bottom surface of the groove 371. Furthermore, regarding the groove 371, the second electrode 380 may be disposed only on a portion of the inner surface of the groove 371, or it may not cover the entire inner surface of the groove 371.

[0176] Additionally, for example, in the first pressure chamber row, such as Figure 16 As shown, the +X direction end 380a of the second electrode 380 is positioned further outward than the end 360a of the first electrode 360 ​​covered by the piezoelectric body 370 on the +X axis direction side. That is, the end 380a of the second electrode 380 is located on the +X axis direction side that is further outward than the end 312a of the pressure chamber 312 and also on the +X axis direction side that is further outward than the end 360a of the first electrode 360. In this embodiment, the end 380a of the second electrode 380 is substantially aligned with the end 370a of the piezoelectric body 370 in the X-axis direction. Therefore, the +X axis direction end of the active portion 410, i.e., the boundary between the active portion 410 and the inactive portion 415, is defined by the end 360a of the first electrode 360.

[0177] On the other hand, the -X-axis end 380b of the second electrode 380 is positioned further outward in the -X-axis direction than the -X-axis end 312b of the pressure chamber 312, and positioned further inward in the +X-axis direction than the end 370b of the piezoelectric body 370. As described above, the end 370b of the piezoelectric body 370 is located further inward in the +X-axis direction than the end 360b of the first electrode 360. Therefore, the end 380b of the second electrode 380 is located on the piezoelectric body 370 which is further in the +X-axis direction than the end 360b of the first electrode 360. Therefore, on the -X-axis direction side of the end 380b of the second electrode 380, there is a portion of the surface of the piezoelectric body 370 exposed.

[0178] Thus, since the end 380b of the second electrode 380 is positioned closer to the +X axis direction than the end 370b of the piezoelectric body 370 and the end 360b of the first electrode 360, the end of the active part 410 in the -X axis direction, i.e., the boundary between the active part 410 and the inactive part 415, is defined by the end 380b of the second electrode 380.

[0179] The material of the second electrode 380 is not particularly limited, and it can be a conductive material, such as a metal like platinum (Pt), iridium (Ir), gold (Au), or titanium (Ti), or a conductive metal oxide like indium tin oxide (ITO), similar to the first electrode 360. Alternatively, it can be formed by stacking multiple materials such as platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti). In this embodiment, iridium (Ir) is used as the second electrode 380.

[0180] Furthermore, a wiring portion 385 is provided on the outer side of the end 380b of the second electrode 380, that is, on the -X-axis direction side of the end 380b of the second electrode 380. This wiring portion 385 is on the same layer as the second electrode 380 but is electrically discontinuous with the second electrode 380. The wiring portion 385 is formed from the piezoelectric body 370 to the first electrode 360, which extends further in the -X-axis direction than the piezoelectric body 370, with a spacing between them and the end 380b of the second electrode 380. This wiring portion 385 is provided independently for each active part 410. That is, multiple wiring portions 385 are arranged at predetermined intervals along the Y-axis direction. Furthermore, the wiring portion 385 may be formed from a different layer than the second electrode 380, but it is preferable to form it from the same layer as the second electrode 380. This simplifies the manufacturing process of the wiring portion 385 and reduces costs.

[0181] Furthermore, on the first electrode 360 ​​and the second electrode 380 constituting the piezoelectric element 60, the first electrode 360 ​​is electrically connected to an independent lead electrode 391, and the second electrode 380 is electrically connected to a common lead electrode 392, which serves as a common electrode for driving. The ends of the independent lead electrode 391 and the common lead electrode 392 opposite to the ends connected to the piezoelectric element 60 are electrically connected to a flexible wiring substrate 420. Multiple wirings for connecting to the control mechanism 10, the temperature information output circuit 26, and multiple circuits (not shown) are formed on the wiring substrate 420. In this embodiment, the wiring substrate 420 is, for example, made of an FPC (Flexible Printed Circuit). Alternatively, it may be made of any flexible substrate such as an FFC (Flexible Flat Cable) instead of an FPC.

[0182] In this embodiment, the independent lead electrode 391 and the common lead electrode 392 extend and are exposed within the through-hole 332 formed in the protective substrate 330, and are electrically connected to the wiring substrate 420 within the through-hole 332. Furthermore, an integrated circuit 421 is mounted on the wiring substrate 420, which includes a drive signal selection circuit 200 that outputs a drive signal VOUT for driving the piezoelectric element 60.

[0183] In this embodiment, the independent lead electrode 391 and the common lead electrode 392 are formed from the same layer, but are electrically discontinuous. Therefore, compared to forming the independent lead electrode 391 and the common lead electrode 392 separately, the manufacturing process can be simplified and costs reduced. Of course, the independent lead electrode 391 and the common lead electrode 392 can also be formed from different layers.

[0184] The materials used for the individual lead electrode 391 and the common lead electrode 392 are not particularly limited as long as they are conductive. For example, gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), platinum (Pt), aluminum (Al), etc., can be used. In this embodiment, gold (Au) is used as both the individual lead electrode 391 and the common lead electrode 392. Furthermore, the individual lead electrode 391 and the common lead electrode 392 may also have a sealing layer to improve their adhesion to the first electrode 360, the second electrode 380, or the vibrating plate 350.

[0185] Individual lead electrodes 391 are provided for each active portion 410, that is, for each first electrode 360. For example... Figure 16 As shown, for example in the first pressure chamber array, the independent lead electrode 391 is connected via the wiring portion 385 to the vicinity of the end 360b of the first electrode 360 ​​disposed outside the piezoelectric body 370, and is actually led out to the vibrating plate 350 on the pressure chamber substrate 310 in the -X axis direction.

[0186] On the other hand, such as Figure 14 As shown, for example in the first pressure chamber array, the common lead electrode 392 extends from the second electrode 380 constituting the common electrode on the piezoelectric body 370 towards the -X direction at both ends in the Y-axis direction to the vibrating plate 350. Furthermore, the common lead electrode 392 has an extension portion 392a and an extension portion 392b. (As shown...) Figure 14 , Figure 16 As shown, for example in the first pressure chamber row, the extension portion 392a extends along the Y-axis in the region corresponding to the end portion 312a of the pressure chamber 312, and the extension portion 392b extends along the Y-axis in the region corresponding to the end portion 312b of the pressure chamber 312. These extension portions 392a and 392b are continuously provided along the Y-axis relative to the plurality of active portions 410.

[0187] Furthermore, the extension portions 392a and 392b extend from the inside of the pressure chamber 312 to the outside of the pressure chamber 312 in the X-axis direction. In this embodiment, the active portion 410 of the piezoelectric element 60 extends to the outside of the pressure chamber 312 at both ends in the X-axis direction, and the extension portions 392a and 392b extend from the active portion 410 to the outside of the pressure chamber 312.

[0188] like Figure 16 As shown, a resistance wiring 401 is provided on the surface of the vibrating plate 350 in the -Z axis direction. The resistance wiring 401 constitutes at least a part of the temperature detection circuit 24 for detecting the temperature of the pressure chamber 312. The temperature detection circuit 24 of this embodiment utilizes the characteristic that the resistance value of a metal or semiconductor changes with temperature. The material of the resistance wiring 401 is not particularly limited as long as the resistance value is temperature-dependent, such as gold (Au), platinum (Pt), iridium (Ir), aluminum (Al), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), etc. Among these, from the viewpoint of large resistance value change due to temperature and high stability and accuracy, platinum (Pt) can be appropriately used as the material of the resistance wiring 401. In this embodiment, the resistance wiring 401 is formed on the surface of the vibrating plate 350 in the -Z axis direction in a manner that is co-layered with the first electrode 360 ​​but electrically discontinuous with the first electrode 360. Therefore, the material of the resistance wiring 401 is platinum (Pt), the same as that of the first electrode 360. Therefore, compared to forming the resistor wiring 401 and the first electrode 360 ​​separately, the manufacturing process can be simplified and costs reduced. Of course, the resistor wiring 401 can also be formed from a different layer than the first electrode 360.

[0189] like Figure 14 As shown, the resistance wiring 401 is continuous. One end of the resistance wiring 401 on the +X-axis side in the X-axis direction is connected to the measuring lead electrode 393a, and the other end of the resistance wiring 401 on the -X-axis side in the X-axis direction is connected to the measuring lead electrode 393b. Furthermore, the measuring lead electrodes 393a and 393b are electrically connected to the wiring substrate 420. Thus, the resistance wiring 401 is electrically connected to the temperature information output circuit 26, which can measure the resistance value of the resistance wiring 401. In this embodiment, the resistance wiring 401 is covered by a piezoelectric element 370 and is located between the vibrating plate 350 and the piezoelectric element 370 in the Z-axis direction.

[0190] The resistor wiring 401 has a first pressure chamber row side meandering pattern on the +X-axis side and a second pressure chamber row side meandering pattern on the -X-axis side. Viewed from the -Z-axis direction, the first pressure chamber row side meandering pattern meanders along the Y-axis direction at a position overlapping with a supply communication channel 319, which communicates with each pressure chamber 312 constituting the first pressure chamber row. Viewed from the -Z-axis direction, the second pressure chamber row side meandering pattern meanders along the Y-axis direction at a position overlapping with a supply communication channel 319, which communicates with each pressure chamber 312 constituting the second pressure chamber row. That is, the resistor wiring 401 has a first pressure chamber row side meandering pattern corresponding to the first pressure chamber row formed by the plurality of pressure chambers 312, and a second pressure chamber row side meandering pattern corresponding to the second pressure chamber row formed by the plurality of pressure chambers 312. Furthermore, as... Figure 15 , Figure 16 As shown, the distance between the end of the pressure chamber 312 on the -Z-axis side and the resistor wiring 401 in the Z-axis direction is shorter than the dimension of the pressure chamber 312 in the Z-axis direction. Furthermore, for example in the first pressure chamber row, the longest distance between the end 312a of the pressure chamber 312 on the +X direction and the resistor wiring 401 in the X-axis direction is shorter than the dimension of the pressure chamber 312 in the X-axis direction. Therefore, the resistance value of the resistor wiring 401 easily changes correspondingly to the temperature change of the pressure chamber 312.

[0191] In this embodiment, the measurement lead electrode 393, which includes measurement lead electrode 393a and measurement lead electrode 393b, is formed from the same layer as the independent lead electrode 391 and the common lead electrode 392, but is electrically discontinuous. Therefore, compared to forming the measurement lead electrode 393 independently from the independent lead electrode 391 and the common lead electrode 392, the manufacturing process can be simplified and costs reduced. Of course, the measurement lead electrode 393 can also be formed on a different layer than the independent lead electrode 391 and the common lead electrode 392.

[0192] The material of the measuring lead electrode 393 is not particularly limited as long as it is conductive; for example, gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), platinum (Pt), and aluminum (Al) can be used. In this embodiment, gold (Au) is used as the measuring lead electrode 393. Therefore, the material of the measuring lead electrode 393 is the same as that of the independent lead electrode 391 and the shared lead electrode 392. In addition, the measuring lead electrode 393 may also have a sealing layer to improve the adhesion with the resistance wiring 401 or the vibrating plate 350.

[0193] In this embodiment, the measuring lead electrode 393 extends and protrudes into a through-hole 332 formed in the protective substrate 330, and is electrically connected to the wiring substrate 420 within the through-hole 332. Thus, the temperature information output circuit 26 can acquire the resistance value of the resistive wiring 401 via the wiring substrate 420. Furthermore, the temperature information output circuit 26 outputs the acquired resistance value of the resistive wiring 401 as a temperature information signal TI based on the temperature acquisition request signal TD from the control circuit 100. Alternatively, the temperature information output circuit 26 can pre-store the correspondence between the resistance value of the resistive wiring 401 and the temperature. Moreover, the temperature information output circuit 26 can also output the temperature corresponding to the resistance value of the resistive wiring 401 as a temperature information signal TI based on the temperature acquisition request signal TD from the control circuit 100.

[0194] For example, when the temperature detection circuit 24 is located outside the ejection module 22, the difference between the temperature measured by the temperature detection circuit 24 and the temperature inside the pressure chamber 312 may be larger than the difference between the temperature inside the ejection module 22 and the temperature inside the pressure chamber 312. In this case, the correction control of the control circuit 100, which corrects the control signals Ctrl-H, Ctrl-C, and Ctrl-T based on the temperature information signal TI, is reduced, and optimal ejection control of the ejection module 22 to the appropriate temperature of the ink inside the pressure chamber 312 may not be possible. In this embodiment, the resistor wiring 401 is stacked on the vibrating plate 350 located inside the ejection module 22. As a result, the difference between the temperature detected based on the resistance value of the resistor wiring 401, which is the temperature detection circuit 24, and the temperature inside the pressure chamber 312 can be reduced, and the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 is improved. As a result, ejection control of the ejection module 22 to the appropriate temperature of the ink inside the pressure chamber 312 can be performed by the control circuit 100.

[0195] That is, the ejection module 22 of the printhead 20 in this embodiment includes: a piezoelectric element 60, which receives and is driven by a drive signal VOUT based on a drive signal COM, and includes a first electrode 360, a second electrode 380, and a piezoelectric body 370. In the Z-axis direction, which is the stacking direction of the first electrode 360, the second electrode 380, and the piezoelectric body 370, the piezoelectric body 370 is located between the first electrode 360 ​​and the second electrode 380; a vibrating plate 350, which is located on the +Z-axis direction side relative to the piezoelectric element 60, which is the stacking direction, i.e., the Z-axis direction, and is deformed under the drive of the piezoelectric element 60; and a pressure chamber substrate 310, which is located on the +Z-axis direction side relative to the piezoelectric element 60. The vibrating plate 350 is located on the +Z-axis side, which is the stacking direction (i.e., the Z-axis direction), and is provided with a plurality of pressure chambers 312 whose volume varies according to the deformation of the vibrating plate 350; a drive signal selection circuit 200 switches whether to supply a drive signal COM to the piezoelectric element 60; a wiring substrate 420 is provided with an integrated circuit 421 including the drive signal selection circuit 200; and a resistor wiring 401 is located on the -Z-axis side, which is the other side of the stacking direction (i.e., the Z-axis direction) relative to the vibrating plate 350, and is electrically connected to the wiring substrate 420, and constitutes at least a part of a temperature detection circuit 24 for detecting temperature information of the pressure chambers 312.

[0196] Therefore, the difference between the temperature detected based on the resistance value of the resistive wiring 401, which serves as the temperature detection circuit 24, and the temperature inside the pressure chamber 312 can be reduced, thereby improving the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24. As a result, the ejection module 22, which is adapted to the temperature of the ink inside the pressure chamber 312, can be ejected via the control circuit 100.

[0197] Furthermore, by stacking at least a portion of the resistive wiring 401, which serves as the temperature detection circuit 24, onto the vibrating plate 350, the resistive wiring 401, which serves as the temperature detection circuit 24, can be positioned closer to the pressure chamber 312, thereby further improving the accuracy of temperature detection of the pressure chamber 312 detected by the temperature detection circuit 24. As a result, the ejection module 22, which controls the temperature of the ink within the pressure chamber 312, can be more effectively controlled by the control circuit 100.

[0198] 6. Temperature detection action

[0199] As described above, in the liquid ejection device 1 of this embodiment, since a resistance wire 401 for detecting the temperature of the ejection module 22 is provided on the vibrating plate 350 inside the ejection module 22 of the printhead 20, the resistance wire 401, which serves as the temperature detection circuit 24, can be placed near the pressure chamber 312 where the ink is stored. This reduces the difference between the temperature detected based on the resistance value of the resistance wire 401 and the temperature inside the pressure chamber 312, thus improving the accuracy of the temperature detection of the pressure chamber 312 detected by the temperature detection circuit 24.

[0200] On the other hand, since the resistor wiring 401, which is the temperature detection circuit 24, is located near the pressure chamber 312 where ink is stored, the following problems may occur.

[0201] From the viewpoint of improving the image quality formed on the medium P, hundreds or more nozzles 321 are densely arranged in the ejection module 22. Therefore, hundreds or more piezoelectric elements 60, corresponding to the hundreds or more nozzles 321, are densely arranged in the ejection module 22. Consequently, signal wiring transmitting the drive signal VOUT supplied to the corresponding piezoelectric element 60 is densely arranged on the vibrating plate 350 in the ejection module 22. When the resistive wiring 401 is arranged on such a vibrating plate 350, the resistive wiring 401 is positioned near the signal wiring transmitting the drive signal VOUT. Therefore, noise generated by voltage changes in the drive signal VOUT may overlap with the resistive wiring 401. If the noise generated by voltage changes in the drive signal VOUT overlaps with the resistive wiring 401, the accuracy of temperature detection of the pressure chamber 312, detected by the temperature detection circuit 24 including the resistive wiring 401, may decrease.

[0202] Furthermore, when the piezoelectric element 60 is driven by the drive signal VOUT, the vibrating plate 350 on which the resistive wiring 401 is stacked is displaced as the piezoelectric element 60 is driven. As a result, the impedance of the resistive wiring 401 changes, and the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistive wiring 401 may also decrease.

[0203] Furthermore, as described above, the ejection module 22 applies pressure to the ink stored in the pressure chamber 312 by changing the volume of the pressure chamber 312 due to the deformation or vibration of the vibrating plate 350 generated by driving the piezoelectric element 60, thereby ejecting ink from the nozzle 321. In this ejection module 22 configuration, since the pressure in the pressure chamber 312 changes during ink ejection, the temperature of the ink stored in the pressure chamber 312 may change instantaneously. Therefore, the detection accuracy of the constant temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistive wiring 401 may also be reduced.

[0204] To address this problem, in the liquid ejection device 1 of this embodiment, a temperature information signal TI is input to the control circuit 100, corresponding to the temperature detection information TH detected by the temperature detection circuit 24 including the resistive wiring 401 during the period when the selection circuit 230 of the drive signal selection circuit 200 does not supply the drive signal COM to the piezoelectric element 60. In other words, the printhead 20 outputs the temperature information signal TI based on the temperature detection information TH detected by the temperature detection circuit 24 including the resistive wiring 401 during the period when the selection circuit 230 of the drive signal selection circuit 200 does not supply the drive signal COM to the piezoelectric element 60.

[0205] Therefore, the possibility of noise overlap due to fluctuations in the voltage value of the drive signal VOUT is reduced. Furthermore, since the piezoelectric element 60 is not driven during the period when the temperature detection circuit 24, including the resistor wiring 401, detects the temperature detection information TH, the possibility of impedance changes in the resistor wiring 401 is reduced, and the possibility of instantaneous temperature changes in the ink stored in the pressure chamber 312 during this period is also reduced. As a result, even when the resistor wiring 401, which is the temperature detection circuit 24, is located near the pressure chamber 312 containing ink, the possibility of reduced accuracy in detecting the temperature of the pressure chamber 312 using the temperature detection circuit 24, including the resistor wiring 401, is reduced. Thus, the temperature detection circuit 24 can detect the temperature of the pressure chamber 312 with high accuracy.

[0206] Here, the period during which the selection circuit 230 of the drive signal selection circuit 200 does not supply the drive signal COM to the piezoelectric element 60 refers to the period during which the trapezoidal waveforms Adp, Bdp, and Cdp contained in the drive signal COM are not supplied to the piezoelectric element 60 as the drive signal VOUT, and the selection circuit 230 is continuously non-conducting during the period tp.

[0207] A specific example of the operation of the liquid ejection device 1 that operates as described above will be explained. Figure 18 This diagram illustrates an example of the timing for acquiring the temperature of the ejection module 22 of the printhead 20.

[0208] The liquid ejection device 1 is started and begins operation by supplying power voltage. At this time, as the initial setting of the liquid ejection device 1, the control circuit 100 maintains the temperature detection flag Ft, which indicates whether the temperature of the pressure chamber 312 needs to be detected by the temperature detection circuit 24, at a level of L, indicating that the temperature does not need to be detected. That is, the control circuit 100 sets the temperature detection flag Ft to "L" (step S10).

[0209] Then, when a printing request is generated relative to the liquid ejection device 1 by inputting an image information signal containing image data from an external device (step S20), the control circuit 100 outputs a control signal Ctrl-C to move the carriage 21 along the scanning axis. As a result, the carriage 21 moves along the scanning axis (step S30).

[0210] The linear encoder 90, moving via the carriage 21, outputs a detection signal to the control circuit 100 based on the scanning position of the carriage 21. The control circuit 100 determines whether the scanning position of the carriage 21, i.e., the scanning position of the printhead 20, is within the printing area based on the input detection signal (step S40). Here, the printing area refers to the area where the printhead 20, mounted on the carriage 21, ejects ink from the medium P, and is defined according to the scanning range of the carriage 21 or the width of the transported medium P along the scanning axis. Furthermore, in the following description, the area outside the aforementioned printing area within the scanning range of the carriage 21 is referred to as the non-printing area.

[0211] When the control circuit 100 determines that the scanning position of the carriage 21 is in the printing area ("Yes" in step S40), the liquid ejection device 1 performs the printing process (step S50). The printing process refers to the process of ejecting ink from the print head 20 to the desired position on the medium P to form the desired image on the medium P, including, for example, the process of the control circuit 100 outputting a head control signal DI corresponding to the image data input from an external device to the print head 20.

[0212] Furthermore, after the printing process is completed within the prescribed travel period, the control circuit 100 determines whether a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 based on the usage status of the liquid ejection device 1 or a request from the user (step S60). When the control circuit 100 determines that a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 ("Yes" in step S60), the control circuit 100 maintains the temperature detection flag Ft at a level H indicating that the temperature of the pressure chamber 312 needs to be detected using the temperature detection circuit 24. That is, the control circuit 100 sets the temperature detection flag Ft to "H" (step S70).

[0213] Furthermore, when the control circuit 100 determines that no temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 ("No" in step S60), or after the control circuit 100 determines that a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24, and sets the temperature detection flag Ft = "H" (step S70), the control circuit 100 determines whether the printing process corresponding to the image data input from the external device has been completed (step S80).

[0214] Furthermore, when the control circuit 100 determines that the printing process is not complete ("No" in step S80), the control circuit 100 determines again, based on the input detection signal, whether the scanning position of the carriage 21, i.e., the scanning position of the print head 20, is in the printing area (step S40). On the other hand, when the control circuit 100 determines that the printing process is complete ("Yes" in step S80), the control circuit 100 stops the carriage 21 from moving (step S140), and the liquid ejection device 1 stops operating.

[0215] When the control circuit 100 determines that the scanning position of the carriage 21 is not in the printing area ("No" in step S40), that is, when the control circuit 100 determines that the scanning position of the carriage 21 is in the area outside the printing area, the control circuit 100 determines whether the temperature detection flag Ft is at the L level, which indicates that the temperature detection circuit 24 does not need to be used to detect the temperature of the pressure chamber 312 (step S90).

[0216] When the temperature detection flag Ft held by the control circuit 100 is at level H ("No" in step S90), the control circuit 100 sets all the ejection data [SIH, SIL] contained in the ejection control signal SI of the head control signal DI to ejection data [SIH, SIL] = [0, 0] and outputs it (step S100). As a result, all the selection circuits 230 contained in the drive signal selection circuit 200 are controlled to be non-conductive.

[0217] Then, the control circuit 100 generates a temperature acquisition request signal TD for acquiring the temperature of the ejection module 22 of the printhead 20, and outputs it to the temperature information output circuit 26. The temperature information output circuit 26 generates a temperature information signal TI corresponding to the temperature detection information TH based on the input temperature acquisition request signal TD, and outputs it to the control circuit 100. This temperature detection information TH is input from the temperature detection circuit 24 and corresponds to the temperature of the pressure chamber 312. Thus, the control circuit 100 acquires the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 (step S110).

[0218] Specifically, the temperature information output circuit 26 holds and amplifies the temperature detection information TH, which is input from the temperature detection circuit 24 at a timing when a temperature acquisition request signal TD is input and corresponds to the temperature of the pressure chamber 312. Furthermore, the amplified signal of the temperature detection information TH is output as the temperature information signal TI. That is, the temperature detection information TH, corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24, is input to the control circuit 100 as the temperature information signal TI. All selection circuits 230 included in the drive signal selection circuit 200 are controlled to be non-conductive. That is, the control circuit 100 is input with the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when all selection circuits 230 are not supplying drive signals COM to the multiple piezoelectric elements 60. In other words, the printhead 20 outputs the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when all selection circuits 230 are not supplying drive signals COM to the multiple piezoelectric elements 60.

[0219] At this time, the temperature information output circuit 26 can, at the timing of the input temperature acquisition request signal TD, retain all the temperature detection information TH1 to THn output by the temperature detection circuit 24 of each of the ejection modules 22-1 to 22-n, and output the amplified signals of the retained temperature detection information TH1 to THn as temperature information signals TI to the control circuit 100. Alternatively, at the timing of the input temperature acquisition request signal TD, it can retain the temperature detection information TH1 to THn specified by the temperature acquisition request signal TD among the temperature detection information TH1 to THn output by the temperature detection circuit 24 of each of the ejection modules 22-1 to 22-n, and output the amplified signals of the retained temperature detection information TH1 to THn as temperature information signals TI to the control circuit 100.

[0220] Then, the control circuit 100 considers the temperature acquisition of the pressure chamber 312 of the ejection module 22 to be complete, and maintains the temperature detection flag Ft at a level L, indicating that the temperature of the pressure chamber 312 does not need to be detected by the temperature detection circuit 24. That is, the control circuit 100 sets the temperature detection flag Ft = "L" (step S120).

[0221] Furthermore, when the carriage's scanning position is outside the printed area and the temperature detection flag Ft held by the control circuit 100 is at level L ("Yes" in step S90), or after the control circuit 100 completes the temperature acquisition of the pressure chamber 312 and sets the temperature detection flag Ft to "L" (step S120), by bringing the carriage 21's scanning position to the designated area, the control circuit 100 outputs a control signal Ctrl-C that reverses the movement direction of the carriage 21. Thus, the carriage 21 moves along the reversed movement direction along the scanning axis. That is, the movement direction is reversed, and the carriage 21 moves along the scanning axis (step S130).

[0222] After the carriage's movement direction is reversed, the control circuit 100 determines whether a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 based on the usage status of the liquid ejection device 1 or a request from the user (step S60). When the control circuit 100 determines that a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 ("Yes" in step S60), the control circuit 100 maintains the temperature detection flag Ft at a level H indicating that the temperature of the pressure chamber 312 needs to be detected using the temperature detection circuit 24. That is, the control circuit 100 sets the temperature detection flag Ft to "H" (step S70).

[0223] Furthermore, when the control circuit 100 determines that no temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 ("No" in step S60), or after the control circuit 100 determines that a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24, and sets the temperature detection flag Ft = "H" (step S70), the control circuit 100 determines whether the printing process corresponding to the image data input from the external device has been completed (step S80).

[0224] Furthermore, when the control circuit 100 determines that the printing process is not complete ("No" in step S80), the control circuit 100 determines again, based on the input detection signal, whether the scanning position of the carriage 21, i.e., the scanning position of the print head 20, is in the printing area (step S40). On the other hand, when the control circuit 100 determines that the printing process is complete ("Yes" in step S80), the control circuit 100 stops the carriage 21 from moving (step S140), and the liquid ejection device 1 stops operating.

[0225] As described above, in the liquid ejection device 1 of this embodiment, the control circuit 100 is input with temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 of the drive signal selection circuit 200 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is located outside the printing area. In other words, the printhead 20 outputs temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 of the drive signal selection circuit 200 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is located outside the printing area.

[0226] Here, the control signals Ctrl-H in the control signals Ctrl-C, Ctrl-T, and Ctrl-H output by the control circuit 100 are an example of control signals, the drive signal COM is an example of a drive signal, and the drive circuit 50 that outputs the drive signal COM is an example of a drive signal output circuit. Furthermore, since the trapezoidal waveforms Adp, Bdp, and Cdp contained in the drive signal COM are supplied to the piezoelectric element 60, the trapezoidal waveforms Adp, Bdp, and Cdp contained in the drive signal COM are also an example of a drive signal. Additionally, the Z-axis direction is an example of a stacking direction; the +Z-axis direction side of the Z-axis direction, which is a stacking direction, is an example of one side of the stacking direction; and the -Z-axis direction side of the Z-axis direction, which is a stacking direction, is an example of the other side of the stacking direction. Furthermore, the selection circuit 230 is an example of a switching circuit. Moreover, the temperature detection circuit 24 is an example of a temperature detection unit, and the temperature detection information TH output by the temperature detection circuit 24 is an example of temperature information.

[0227] 7. Effects

[0228] As described above, in the liquid ejection device 1 of this embodiment, a temperature information signal TI is input to the control circuit 100, corresponding to the temperature detection information TH detected by the temperature detection circuit 24, which includes the resistive wiring 401, during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60. That is, in the printhead 20 of this embodiment, the temperature information signal TI based on the temperature detection information TH detected by the temperature detection circuit 24, which includes the resistive wiring 401, during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 is output. As a result, the possibility of noise overlap due to the voltage value of the drive signal VOUT is reduced, and the possibility of impedance change of the resistive wiring 401 is reduced during the period when the temperature detection circuit 24 detects the temperature of the pressure chamber 312 and outputs it as temperature detection information TH. Furthermore, the possibility of instantaneous temperature change of the ink stored in the pressure chamber 312 during this period is also reduced.

[0229] As a result, even when the resistor wiring 401 of the temperature detection circuit 24 is located near the pressure chamber 312 containing ink, the possibility of a decrease in the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 is reduced, thereby enabling the temperature detection circuit 24 to detect the temperature of the pressure chamber 312 with high accuracy.

[0230] Furthermore, by inputting temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is located outside the printing area, the printhead 20 outputs temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 of the drive signal selection circuit 200 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is located outside the printing area. Thus, even when the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 is input to the control circuit 100, the temperature detection circuit 24 detecting the temperature of the pressure chamber 312 will not hinder the ink from being ejected from the printhead 20, that is, the formation of an image on the medium P.

[0231] Therefore, when the temperature of the pressure chamber 312 is detected by the temperature detection circuit 24, there is no need to set a special period, the possibility of the ink ejection speed decreasing is reduced, and the possibility of the image quality formed on the medium P decreasing when the temperature of the pressure chamber 312 is detected by the temperature detection circuit 24 is also reduced.

[0232] 8. Variations

[0233] In the liquid ejection device 1 of this embodiment described above, it was explained that temperature detection information TH, corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is located outside the printing area, is input to the control circuit 100. The printhead 20 outputs temperature detection information TH, corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is located outside the printing area. However, in the liquid ejection device 1, it is also possible to input temperature detection information TH, corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is stopped, to the control circuit 100. The printhead 20 may also output temperature detection information TH, corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is stopped.

[0234] A specific example of the operation of the modified liquid ejection device 1 will be explained. Figure 19 This is a diagram illustrating an example of the timing for acquiring the temperature of the ejection module 22 in a modified liquid ejection device 1. Furthermore, in Figure 19 In this document, the same reference numerals are used to indicate the same components and steps as those described in the above embodiments.

[0235] By supplying power voltage to the liquid ejection device 1, the liquid ejection device 1 maintains the temperature detection flag Ft at level L as an initial setting. That is, the control circuit 100 sets the temperature detection flag Ft to "L" (step S10). Then, when a printing request is generated relative to the liquid ejection device 1 by inputting an image information signal containing image data, etc., from an external device (step S20), the carriage 21 is moved along the scanning axis under the control of the control circuit 100 (step S30). Furthermore, the control circuit 100 determines whether the scanning position of the carriage 21 and the print head 20 is in the printing area based on the detection signal input as the carriage 21 moves (step S40).

[0236] When the control circuit 100 determines that the scanning position of the carriage 21 is in the printing area ("Yes" in step S40), the liquid ejection device 1 performs the printing process (step S50). Furthermore, after the printing process is completed within the specified stroke period, the control circuit 100 determines whether a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 (step S60). When the control circuit 100 determines that a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 ("Yes" in step S60), the control circuit 100 sets the temperature detection flag Ft to "H" (step S70).

[0237] Furthermore, when the control circuit 100 determines that no temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24 ("No" in step S60), or after the control circuit 100 determines that a temperature detection request has been generated to detect the temperature of the pressure chamber 312 using the temperature detection circuit 24, and sets the temperature detection flag Ft = "H" (step S70), the control circuit 100 determines whether the printing process corresponding to the image data input from the external device has been completed (step S80). Moreover, when the control circuit 100 determines that the printing process has not been completed ("No" in step S80), the control circuit 100 again determines whether the scanning positions of the carriage 21 and the print head 20 are in the printing area based on the input detection signal (step S40). On the other hand, when the control circuit 100 determines that the printing process has been completed ("Yes" in step S80), the control circuit 100 stops the carriage 21 from moving (step S140), and the liquid ejection device 1 stops operating.

[0238] When the control circuit 100 determines that the scanning position of the carriage 21 is not in the printing area ("No" in step S40), that is, when the control circuit 100 determines that the scanning position of the carriage 21 is outside the printing area, the control circuit 100 determines whether the scanning position of the carriage 21 is in the reversal area (step S52). Here, the reversal area refers to the area where the scanning direction of the carriage 21 is reversed. When the control circuit 100 determines that the scanning position of the carriage 21 is not in the reversal area ("No" in step S52), it proceeds to step S60. On the other hand, when the control circuit 100 determines that the scanning position of the carriage 21 is in the reversal area ("No" in step S52), the control circuit 100 stops the carriage 21 (step S54).

[0239] Furthermore, after the carriage 21 stops, the control circuit 100 determines whether the temperature detection mark Ft is at the L level (step S90).

[0240] When the temperature detection flag Ft held by the control circuit 100 is at level H ("No" in step S90), the control circuit 100 sets all the ejection data [SIH, SIL] contained in the ejection control signal SI of the head control signal DI to ejection data [SIH, SIL] = [0, 0] and outputs it (step S100). As a result, all selection circuits 230 contained in the drive signal selection circuit 200 are controlled to be non-conductive. Then, the control circuit 100 generates a temperature acquisition request signal TD for acquiring the temperature of the ejection module 22 of the printhead 20 and outputs it to the temperature information output circuit 26. The temperature information output circuit 26 generates a temperature information signal TI corresponding to the temperature detection information TH based on the input temperature acquisition request signal TD and outputs it to the control circuit 100. This temperature detection information TH is information input from the temperature detection circuit 24 and corresponds to the temperature of the pressure chamber 312. Thus, the control circuit 100 acquires the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 (step S110).

[0241] Then, the control circuit 100 considers the acquisition of the temperature of the pressure chamber 312 of the ejection module 22 to be complete, and maintains the temperature detection flag Ft at the L level. That is, the control circuit 100 sets the temperature detection flag Ft = "L" (step S120).

[0242] Furthermore, when the carriage's scanning position is outside the printed area and the temperature detection flag Ft held by the control circuit 100 is at level L ("Yes" in step S90), or after the control circuit 100 completes the temperature acquisition of the pressure chamber 312 and sets the temperature detection flag Ft to "L" (step S120), the control circuit 100 outputs a control signal Ctrl-C that reverses the movement direction of the carriage 21. As a result, the carriage 21 moves along the reversed movement direction along the scanning axis. That is, the movement direction is reversed, and the carriage 21 moves along the scanning axis (step S130). After the carriage's movement direction is reversed, the process proceeds to step S60.

[0243] In the modified liquid ejection device 1 and printhead 20 configured as described above, by inputting temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is stopped, the control circuit 100 is supplied with temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 during the period when the selection circuit 230 does not supply the drive signal COM to the piezoelectric element 60 and the carriage 21 is stopped. This reduces the likelihood that noise generated by cable slippage or vibration of the carriage 21 due to the movement of the carriage 21 will overlap with the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24. As a result, even when the resistive wiring 401 of the temperature detection circuit 24 is located near the pressure chamber 312 containing ink, the possibility of reduced accuracy in detecting the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 is further reduced, allowing the temperature detection circuit 24 to detect the temperature of the pressure chamber 312 with even higher accuracy.

[0244] The embodiments and variations have been described above, but the present invention is not limited to these embodiments and can be implemented in various ways without departing from its spirit. For example, the above embodiments can also be appropriately combined.

[0245] This invention includes configurations that are substantially the same as those described in the embodiments (e.g., configurations with the same function, method, and result, or configurations with the same purpose and effect). Additionally, this invention includes configurations that replace non-essential parts of the configurations described in the embodiments. Furthermore, this invention includes configurations that can achieve the same effects as those described in the embodiments or that can achieve the same purpose. Additionally, this invention includes configurations incorporating known techniques into the configurations described in the embodiments.

[0246] The following can be derived from the above implementation methods.

[0247] One embodiment of a liquid ejection device includes: a control circuit that outputs a control signal; a drive signal output circuit that outputs a drive signal; and a printhead that receives the control signal and the drive signal and ejects liquid. The printhead includes: a piezoelectric element comprising a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located between the first electrode and the second electrode in a stacking direction of the first electrode, the second electrode, and the piezoelectric body, and the piezoelectric element is driven by the drive signal; and a vibrating plate located on one side of the piezoelectric element in the stacking direction, and vibrating under the drive of the piezoelectric element. The device comprises: a pressure chamber substrate located on one side of the stacking direction relative to the vibrating plate, and having a plurality of pressure chambers whose volume varies according to the deformation of the vibrating plate; a switching circuit for switching whether to supply the drive signal to the piezoelectric element; a wiring substrate having the switching circuit; and a temperature detection unit located on the other side of the stacking direction relative to the vibrating plate and electrically connected to the wiring substrate, which detects the temperature information of the pressure chambers. The liquid ejection device inputs the temperature information detected by the temperature detection unit to the control circuit during the period when the switching circuit does not supply the drive signal to the piezoelectric element.

[0248] According to this liquid ejection device, by placing a temperature detection unit inside the printhead including a piezoelectric element, the temperature information of the pressure chamber can be detected with high precision. Furthermore, the temperature information detected by the temperature detection unit during the period when the switching circuit does not supply a drive signal to the piezoelectric element is input to the control circuit. That is, when the temperature detection unit detects the temperature information of the pressure chamber, the drive signal output by the drive circuit is not supplied to the piezoelectric element, but is maintained at a certain voltage value. This reduces the possibility of interference between the drive signal and the temperature information detected by the temperature detection unit input to the control circuit. As a result, the accuracy of the temperature information detected by the temperature detection unit input to the control circuit is improved.

[0249] In one embodiment of the liquid ejection device described above, at least a portion of the temperature detection unit may be stacked on the vibrating plate.

[0250] According to this liquid ejection device, the temperature detection unit can be positioned closer to the pressure chamber, further improving the accuracy of the temperature detection unit in detecting the temperature of the pressure chamber.

[0251] In one embodiment of the liquid ejection device described above, the printhead may include: a plurality of piezoelectric elements; and a plurality of switching circuits, which switch between supplying the drive signal to the plurality of piezoelectric elements, and the liquid ejection device inputs the temperature information detected by the temperature detection unit to the control circuit during the period when all of the plurality of switching circuits are not supplying the drive signal to the plurality of piezoelectric elements.

[0252] According to this liquid ejection device, even when multiple piezoelectric elements are present, the temperature information detected by the temperature detection unit is input to the control circuit during the period when multiple switching circuits do not supply drive signals to all multiple piezoelectric elements. That is, while the temperature detection unit detects the temperature information of the pressure chamber, the drive signals output by the drive circuits are not supplied to all multiple piezoelectric elements, but are maintained at a certain voltage value. Therefore, even when multiple piezoelectric elements are present, the possibility of interference between the drive signals and the temperature information detected by the temperature detection unit input to the control circuit is reduced. As a result, the accuracy of the temperature information detected by the temperature detection unit input to the control circuit is improved.

[0253] In one embodiment of the liquid ejection device described above, it may also include a carriage capable of reciprocating along a scanning axis, the scanning axis intersecting the transport direction of the transport medium, the print head mounted on the carriage, and the liquid ejection device inputting the temperature information detected by the temperature detection unit to the control circuit during the period when the switching circuit does not supply the drive signal to the piezoelectric element and the carriage is located outside the printing area.

[0254] According to this liquid ejection device, the possibility of noise generated during printing on the medium interfering with the temperature information of the pressure chamber detected by the temperature detection unit is reduced. Therefore, the accuracy of the temperature information detected by the temperature detection unit input to the control circuit is further improved.

[0255] In one embodiment of the liquid ejection device described above, it may also include a carriage capable of reciprocating along a scanning axis, the scanning axis intersecting the transport direction of the transport medium, the printhead mounted on the carriage, and the liquid ejection device inputting the temperature information detected by the temperature detection unit to the control circuit during the period when the switching circuit does not supply the drive signal to the piezoelectric element and the carriage is stopped.

[0256] According to this liquid ejection device, the possibility of vibration or noise generated by the movement of the carriage interfering with the temperature information of the pressure chamber detected by the temperature detection unit is reduced. As a result, the accuracy of the temperature information detected by the temperature detection unit input to the control circuit is further improved.

[0257] In one embodiment of the liquid ejection device described above, the drive signal output circuit may include a D-stage amplifier circuit.

[0258] One method of the printhead is to receive a control signal output from a control circuit and a drive signal output from a drive signal output circuit and eject liquid. The printhead includes: a piezoelectric element, including a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located between the first electrode and the second electrode in a stacking direction of the first electrode, the second electrode, and the piezoelectric body, and the piezoelectric element is driven by the drive signal; a vibrating plate, located on one side of the stacking direction relative to the piezoelectric element, and deformed under the drive of the piezoelectric element; a pressure chamber substrate, located on the same side of the stacking direction relative to the vibrating plate, and provided with a plurality of pressure chambers whose volume varies according to the deformation of the vibrating plate; a switching circuit, switching whether to supply the drive signal to the piezoelectric element; a wiring substrate, provided with the switching circuit; and a temperature detection unit, located on the other side of the stacking direction relative to the vibrating plate and electrically connected to the wiring substrate, and detecting the temperature information of the pressure chambers. The printhead outputs the temperature information detected by the temperature detection unit during the period when the switching circuit does not supply the drive signal to the piezoelectric element.

[0259] According to this printhead, by placing the temperature detection unit inside the printhead, which includes a piezoelectric element, the temperature information of the pressure chamber can be detected with high precision. Furthermore, the temperature information detected by the temperature detection unit during the period when the switching circuit does not supply a drive signal to the piezoelectric element is output. That is, when the temperature detection unit detects the output temperature information of the pressure chamber, no drive signal output from the drive circuit is supplied to the piezoelectric element, but it is maintained at a certain voltage value. Therefore, the possibility of interference between the drive signal and the temperature information detected by the temperature detection unit is reduced.

[0260] In one embodiment of the above-described printhead, at least a portion of the temperature sensing section may be stacked on the vibrating plate.

[0261] Based on this printhead, the temperature detection unit can be positioned closer to the pressure chamber, further improving the accuracy of temperature detection in the pressure chamber.

[0262] In one embodiment of the above-described printhead, the printhead may include: a plurality of piezoelectric elements; and a plurality of switching circuits, which switch between supplying the drive signal to the plurality of piezoelectric elements and not supplying the drive signal to the plurality of piezoelectric elements. The printhead outputs the temperature information detected by the temperature detection unit during the period when all of the plurality of switching circuits are not supplying the drive signal to the plurality of piezoelectric elements.

[0263] According to this printhead, even when multiple piezoelectric elements are present, the temperature information detected by the temperature detection unit is output during the period when multiple switching circuits do not supply drive signals to all multiple piezoelectric elements. That is, while the temperature detection unit detects the temperature information of the output pressure chamber, it does not supply drive signals from all drive circuits to all multiple piezoelectric elements, but maintains a certain voltage value. Therefore, even when multiple piezoelectric elements are present, the possibility of interference between the drive signals and the output temperature information is reduced.

[0264] In one embodiment of the above-described printhead, the printhead may be mounted on a carriage capable of reciprocating along a scanning axis, the scanning axis intersecting the transport direction of the transport medium, and the printhead outputs the temperature information detected by the temperature detection unit during the period when the switching circuit does not supply the drive signal to the piezoelectric element and the carriage is located outside the printing area.

[0265] This printhead reduces the likelihood of noise generated during printing on the medium interfering with the temperature information detected by the pressure chamber of the temperature detection unit. Consequently, the accuracy of the temperature information detected by the temperature detection unit, which is input to the control circuit, is further improved.

[0266] In one embodiment of the above-described printhead, the printhead may be mounted on a carriage capable of reciprocating along a scanning axis, the scanning axis intersecting the transport direction of the transport medium, and the printhead outputs the temperature information detected by the temperature detection unit during the period when the switching circuit does not supply the drive signal to the piezoelectric element and the carriage is stopped.

[0267] This printhead design reduces the likelihood of vibrations or noise generated during carriage movement interfering with the temperature information detected by the temperature sensing unit in the pressure chamber. Consequently, the accuracy of the temperature information detected by the temperature sensing unit, which is input into the control circuit, is further improved.

[0268] In one embodiment of the above-described printhead, the printhead may also receive the drive signal output by the drive signal output circuit, which includes a D-level amplifier circuit, and eject liquid.

Claims

1. A liquid ejection device, characterized in that, have: Control circuit, output control signal; Drive signal output circuit, outputs drive signal; The carriage is configured to reciprocate along a scanning axis that intersects the transport direction in which the medium is transported; as well as The printhead receives the control signal and the drive signal and ejects liquid; the printhead is mounted on the carriage. The printhead includes: A piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body. In the stacking direction of the first electrode, the second electrode, and the piezoelectric body, the piezoelectric body is located between the first electrode and the second electrode. The piezoelectric element receives the driving signal to be driven. The vibrating plate is located on one side of the stacking direction relative to the piezoelectric element and deforms under the drive of the piezoelectric element; A pressure chamber substrate is located on one side of the stacking direction relative to the vibrating plate, and is provided with a plurality of pressure chambers whose volume varies according to the deformation of the vibrating plate; A switching circuit to switch whether to supply the drive signal to the piezoelectric element; Wiring substrate, provided with the aforementioned switching circuit; and The temperature detection unit is located on the opposite side of the stacking direction relative to the vibrating plate, and is electrically connected to the wiring substrate, and detects the temperature information of the pressure chamber. The liquid ejection device inputs the temperature information detected by the temperature detection unit to the control circuit during the period when the switching circuit does not supply the drive signal to the piezoelectric element and the slide is stopped and located in the region that causes the slide to reverse along the scanning direction of the scanning axis, i.e., the reversal region.

2. The liquid ejection device according to claim 1, characterized in that, At least a portion of the temperature detection unit is stacked on the vibrating plate.

3. The liquid ejection device according to claim 1, characterized in that, The printhead includes: Multiple piezoelectric elements; and Multiple switching circuits switch between supplying the drive signal to the multiple piezoelectric elements. The liquid ejection device inputs the temperature information detected by the temperature detection unit to the control circuit during the period when all of the plurality of switching circuits are not supplying the drive signal to the plurality of piezoelectric elements.

4. The liquid ejection device according to claim 1, characterized in that, The temperature detection unit detects the temperature information while the carriage is located outside the printing area where the print head is not spraying liquid onto the medium.

5. The liquid ejection device according to any one of claims 1 to 4, characterized in that, The drive signal output circuit includes a D-stage amplifier circuit.

6. A printhead, characterized in that, The print head receives control signals from the control circuit and drive signals from the drive signal output circuit, and ejects liquid. The print head includes: A piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body. In the stacking direction of the first electrode, the second electrode, and the piezoelectric body, the piezoelectric body is located between the first electrode and the second electrode. The piezoelectric element receives the driving signal to be driven. The vibrating plate is located on one side of the stacking direction relative to the piezoelectric element and deforms under the drive of the piezoelectric element; A pressure chamber substrate is located on one side of the stacking direction relative to the vibrating plate, and is provided with a plurality of pressure chambers whose volume varies according to the deformation of the vibrating plate; A switching circuit to switch whether to supply the drive signal to the piezoelectric element; The wiring substrate is provided with the aforementioned switching circuit; as well as The temperature detection unit is located on the opposite side of the stacking direction relative to the vibrating plate, and is electrically connected to the wiring substrate, and detects the temperature information of the pressure chamber. The printhead is mounted on a carriage configured to reciprocate along a scanning axis that intersects the transport direction of the medium. The printhead outputs the temperature information detected by the temperature detection unit during the period when the switching circuit does not supply the drive signal to the piezoelectric element and the carriage stops and is located in the region that causes the carriage to reverse along the scanning direction of the scanning axis, i.e., the reversal region.

7. The printhead according to claim 6, characterized in that, At least a portion of the temperature detection unit is stacked on the vibrating plate.

8. The printhead according to claim 6, characterized in that, have: Multiple piezoelectric elements; as well as Multiple switching circuits switch between supplying the drive signal to the multiple piezoelectric elements. The printhead outputs the temperature information detected by the temperature detection unit during the period when all of the plurality of switching circuits are not supplying the drive signal to the plurality of piezoelectric elements.

9. The printhead according to claim 6, characterized in that, The printhead outputs the temperature information detected by the temperature detection unit during the period when the carriage is located outside the printing area where the printhead is not spraying liquid onto the medium.

10. The printhead according to any one of claims 6 to 9, characterized in that, The printhead receives the drive signal output by the drive signal output circuit, which includes a D-level amplifier circuit, and ejects liquid.

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